It depends on how the patterned Billy is made. On a regular Billy, the backing is a folded up board and looks pretty bad. When I took mine apart to apply paper to the backing, I really struggled with the bending and had to reinforce the back to keep it from bowing and ripping or warping the paper. If the patterned Billys are just the same thing but with stronger paper and glue, I wouldn't be inclined to buy it. If the board is one piece that doesn't bend, though, I might.

I did this a couple of years ago -- I had some white half-height Billys and I sprayed the backer with spray adhesive, then laid down fabric that complemented the room and used a credit card to smooth it out. As Pi mentioned, the backer was very flimsy, but I stretched it taut and used a staple gun to secure it firmly. Then I made sure any excess fabric was stapled down or trimmed. They don't even look like IKEA that way :)

You can see the back panel in your Billy bookcases? I can't. ;)

Just bought this over the weekend and looooooove it. Looks so cool with the contrast of the book colors. Personally, for how affordable it is and how much time it would take to DIY, it wasn't a debate. But I'm lazy that way.

I guess I don't get it? If someone actually put the books back in the bookcase, you wouldn't see much of the pattern at all. Stacking books next to a bookcase seems rather odd.

This has inspired me to mod the wardrobes I'm installing this weekend. I'd been debating back and forth about whether to get white Pax to have it be lighter inside or brown-black Pax to have the exterior match the room better, now I realize I can paint the inside or the wallpaper the outside to make them work better.

I don't get it either. How can you see the pattern if you have books on your shelf?

I did this by just using thumbtacks to hold up some patterned fabric on the backing of the bookcase.

To those of you that "don't get it" - I suppose the idea works best when you stage your bookcase, rather than use them like library shelves. A few books the "right" way, then a knick-knack (candle, globe, vase, camera, whatever), then some larger books stacked horizontally, then a few more vertically, etc. There would be peeks of the pattern and it would add more interest to the space. Plus, imagine it with smaller books and/or DVDs - lots of pattern pop!

an old roommate of mine found a patterned Billy in the scratch and dent section of a local IKEA. it looked nicer than the standard. also - the shelves have the pattern as well - not just the back panel.

Just remember that if you're going to glue something to a thin backing panel like this you will need to do both sides. Adhered materials create a pull on the original object and cause the curling/warping that's really common, you can counter that by creating an opposing pull on the back side.

I think I'd rather use one color of paint, maybe copper...

I like the backing - but I'm partial to something I can change. I used foam core wrapped in fabric and love that I can swap it out for a new style whenever I update my room. You can see it here: http://soprettyisasprettydoes.com/2013/04/22/abrighterbookcase/#more-498