If you can't find one, it seems to me that you could make a free-standing structure to hang a shower surtain from PVC pipes. If designed correctly, it could be put around the shower when you have guests, and disassembled when you want to put it away.

I've never heard of one... One option could be to buy a regular screen and apply a wipeable, waterproof surface to the back, like a roll-on coating, or even sheets of thin plexi. Or you could a folding screen out of thicker frosted plexi, which would stand up on it's own when unfolded, accordion style.

How much water actually gets on the floor when you use it?

With a deluge shower head, I've noticed that the water tends to go down, not out, so if we are talking about only a few shops, then I would go with one of those accordion room dividers (most likely wooden), and then use a floor towel or a rug to pick up the stray dots.

If there's a lot of water, you could use a free standing clothes rack (something like this http://www.mercantila.com/p/fol-d-rak-foldable-and-portable-free-standing-garment-rack ) that you could run a curtain along. That may not be as feasible for taking down every day, but it could work very well for the long weekend that your guests are there.

If you create something on your own, you may want to test how your bath products interact with the material. Metal screen may rust or maybe soap will stick in the openings of a non-metal screen. Plexiglass may etch.

When you say "no shower walls," are you referring to a free-standing tub, like the one that's pictured?

If so, then find a local stainless steel fabricator and have them make one for you out of SS tubing. It would actually be quite easy for them to make one that can be assembled/disassembled with ease.

Have them fabricate a rectangular "ring" as the curtain rod, which attaches to two vertical rods (one on each side), which in turn attach to some type of base for the feet.

What about doing something like a rolling rack in pipe with a shower curtain hainging on it?

Most portable shower curtains are for outdoor use and are quite ugly.

You might want to seriously rethink the installed track in the ceiling. It sounds quite novel and pretty - and you could certainly use it in a graphic sense (draw with the line) if you're worried it would look too utilitarian.

If you can't find anything commercially, and you're willing to spend cash on getting exactly what you want, you can make a few sketches of what you want and then shop around for any local machinists or blacksmiths who could make a beautiful but moveable shower rack for you. If you go that way, I would suggest possibly going for a smaller, round curtain to just go under the showerhead instead of trying to circle the entire bathtub - making something as round as an entire tube but also able to fold up and go in a closet would be very difficult.

We've done this before... Just get a tension bar at the hardware store (the have rubber stoppers on the end), and hang your curtain.

How about one of those pull strings (or wires) like they have in hotels to dry clothes on? You could pull it across, hang a curtin, and when guests are gone the string goes back into it's holder. Maybe you would need two - one for each side of the tub. The white polyester shower liners with gromets are lightweight and should be ok on the string.

Some friends of mine have a lovely oval rod that hangs from the ceiling just around their clawfoot tub, not running into the closet or anything. I would recommend that.

Personally, I don't think that a folding screen would solve your problem of getting water on the floor because any water deflected by the screen would just run down it and onto the floor, not into the tub. I have lived in France with no shower curtain, and I find that you get used to it and become adept at not spraying water everywhere, but your guests probably will not have enough time for that. If the toilet is in the same room, I would recommend one of those metal covers for your toilet paper in any case.

I agree with dburnett that a retractable clothesline or two is a possibility, or you could put a rod like the ceiling one I described on a demountable stand.

I think the retractable clothesline idea would be the easiest - and it would be wall-mounted, not ceiling-mounted.

One of those clothes racks w/ wheels, as they usually fold down pretty easily and can be stored under a bed when not needed. Just hang the shower liner on that when needed.

If it's a guest bath I assume you want it look pretty when they are using it - I don't think anything portable will look nice. Also, even with the downward facing spray, the water can bounce off of the person once they're in the shower. I would hang an oval rod from the ceiling and put a permanent curtain. Maybe your bathroom is set up where you can use a nice thick fabric one and pull it to one side so it looks like a regular curtain when not in use and doesn't take away from the look of the tub.

I've stayed in hotels where there are no shower curtains and the shower is curbless.

I gotta say that the feeling of showering "out in the open" without worrying about curtains, doors, overspray, etc. is rather liberating and makes showering that much more enjoyable.

If your bathtub sits parallel to a wall it might be kind of pretty to revisit your track idea and mount it (on the ceiling) parallel to that wall and then have it come forward and curve around the tub (if that makes any sense). Buy a basic liner and a beautiful fabric that would double as a wall hanging when the curtain is open. (seriously, does that make any sense? because in my head it does and it could really be beautiful if done correctly)... Open the curtain/wall hanging would need to extend past the tub a bit on either side in order to get the look i'm going for...

If the shower head is ceiling mounted maybe you could try to rig something up like this that is removable:

http://www.google.ca/imgres?imgurl=http://www.victoriana.com/Claw-Foot-Tub/images/claw-foot-tub-3.jpg&imgrefurl=http://clawfoottubblog.blogspot.com/2009/08/clawfoot-bathtubs-various-styles-and.html&usg=__6Pod_eDYJtZeQ_-5AZRqJw-U8WE=&h=361&w=300&sz=52&hl=en&start=0&zoom=1&tbnid=e_vvEaSMp1WWMM:&tbnh=128&tbnw=106&prev=/images%3Fq%3Dfree%2Bstanding%2Bshower%2Bcurtain%2Bclawfoot%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26biw%3D1122%26bih%3D533%26tbs%3Disch:1&um=1&itbs=1&iact=rc&dur=549&ei=H1W_TIqHG82X4gaemNDvAQ&oei=H1W_TIqHG82X4gaemNDvAQ&esq=1&page=1&ndsp=20&ved=1t:429,r:3,s:0&tx=77&ty=71

What about fashioning something in the style of a mosquito net? You can install one hook in the ceiling and just hang it/take it down when needed.

Suspend an old ladder from the ceiling like one would for a kitchen pot rack. When guests come attach the shower curtain to the ladder rungs. When the guests are gone, have a beautiful piece of art hanging in your bathroom.

If the tub in your house is like the one in the picture, I would get two curved standard shower rods, (like this http://tinyurl.com/28xkbpn) in a matte finish and install them to the ceiling on each wide side of the tub. That way you can put one shower curtain on each rod and your guests can completely enclose the tub if they choose. Also when they are not in use the curtains can be pulled to opposite sides of the tub and create a beautiful frame for your free-standing tub. I would get some beautiful, extra long curtains that will be simple yet dramatic (like this one: http://tinyurl.com/37dalel).

Ooh, and I just thought, you could hang the rods with white fish hooks in the ceiling, and if you wanted to remove them when the guests shower wasn't in use and store the curtains and rods away it'll be super easy.