You could always go with a wooden christmas tree like:
http://www.shelterness.com/5-diy-wooden-tabletop-christmas-trees/pictures/15044/

or a paper scherenschitte one like:
http://craftfloozy.wordpress.com/2012/02/29/the-art-of-scherenschnitte/

Have you considered a potted Norfolk Pine? It's a living tree (so you treat it just like a houseplant, ie. no fire hazard!) that you can keep inside during the winter months and put outside in warmer weather. They look very seasonal, especially when decorated.

I'm not sure where i saw it (probably AT) but there is a Hanging Spiral Xmas Tree that you can suspend from your ceiling. I found something similar here:

http://www.toxel.com/inspiration/2010/12/22/cool-and-unique-christmas-trees/

Also, I like the "hanging ornaments in the shape of a tree" idea. Hope this helps!

I bought two yards of "Margareta" fabric at IKEA (two yards = a full evergreen tree): http://www.ikea.com/us/en/catalog/products/30234615/

An IKEA display room had the fabric hanging on a wall with tree ornaments, and it looked great. I plan to attach a string of lights using safety pins or something along those lines.

If you're really concerned about fire and that's the only reason for not getting a live tree, get LED Christmas lights and make sure your tree is well watered - the best way to do this is to cut your own (so it's not sitting in a yard for who knows how long) and then cut off a bit more trunk right before putting it into the stand, just like you cut flowers before you put them in the vase.

Then just make sure to water it every day. Also, I believe furs tend to be a bit 'wetter' of a tree than spruce. Although I'm not positive on that one.

Rosemary is another potted houseplant/herb that is popular for some folks.
I can't tell if you want to avoid all houseplants, decorating and lighting a tree, or just lighting a tree.
Sounds like you want to avoid the lighting, but possibly the decorating too.

The Ikea fabric option might work- no lights needed, decorating optional.
One of my grandmothers used a candy gumdrop tree with just mini ornaments hanging on it. Was plastic and she didn't bother with lighting it.

Feather trees, stick trees, etc seem to rarely be lighted.
There are the trending ornaments hung in a spiral floor to ceiling. you might try painting a tree design on a metal surface and adding magnets to the dried surface to be ornaments.

For those lighting real or fake trees, check your wiring every year. Attic and basement high temps can make the wire deteriorate, whether or not the tree is dried out. Also, check your home's electrical.

I'm also not a huge fan of artificial trees - at least the ones that are supposed to look like a live tree. I've always wanted to try one of the aluminum trees in pink, purple or blue. They strike me as wonderfully retro in a wacky and safe way!

Here is an option that I love. Planning on using it myself.
http://www.westelm.com/products/wooden-wall-tree-d357/?pkey=cdecor-holiday

If you are total geek or book worm like me, this might work: a tree made out of hardcover books http://pretiosa.tumblr.com/post/2350313637/prettybooks-by-kristen-mcquillin. I am a poor grad student who is not short on books, so that is what I am doing this year. More paper-based ideas here: http://www.homelife.com.au/decorating/galleries/crafty+christmas+decorating+ideas,10283?pos=4

I also found and LOVE this DIY tree made out of suspended ornaments, but I don't want to put a hole in my ceiling, does anyone have any ideas on how I can do this?

http://www.notmartha.org/archives/2010/12/21/christmas-tree-ornament-mobile-how-to/

There's a great tree-shaped succulent arrangement here, at the bottom of the page:

http://modvintagelife.blogspot.com/2011/03/succulents.html

You could go with a living tree. They tend to be much smaller but you can plant them when the season is over and feel good about it. I do think it's funny to fear tree fires though. From what I can find an average 13 people die each year As opposed to 40,000+ auto deaths.

I also had to give up a real tree recently (new landlord won't allow them) and instead of feeling bummed about a fake-but-attempting-to-look-real tree, I went all out on a gold tinsel tree. It's super cute, and isn't trying to be a substitute tree.

Personally I'm going with a rosemary plant. And assuming I can keep it alive (I could kill tumbleweed), I'll plant it outside in the spring.
When I was a kid my mom used to do a "waterfall" of lights down one of walls. It was really striking and MUCH easier to clean up than a live tree!

Thanks for all the non-live-anything ideas...we are going to be away from home for 10 days over Christmas visiting family/friends. I still want to decorate earlier in December, but not with something that's going to die while we're gone!

http://www.anthropologie.com/anthro/product/home-holdecorwrap/A25659590.jsp

love this one.

I second the living Norfolk pine, or something smaller and / or local that you can plant in spring. Trees don't just burst into flames, in fact to stay alive they must draw water up their trunk so arguably they could be more fireproof than the alternatives as long as they're living, small enough to catch needles in a tray beneath and kept in an open (non lamp) area.

Woah that is cool. Thanks, Kat!

Any collection of items with a common property (color, reflectivity, material) hung or arranged in the shape of a tree will do.