I seriously considered scratching an itx box a couple of months back. I wanted it to look sort of 'centre-piece'-y so I came up with a design using stacked sheets with appropriate steel spacers. Like this:
__________
|_________|
|____|____|
The bottom layer was for the DVD, HDD and PSU (only the front portion is split in half and the top layer housed the mobo etc. Only had a footprint of 190mm by 190mm.
This design allowed me to simply bolt it all together rather than having to faff with bending or gluing the acrylic, and it would have only cost ~£20 to have it laser cut (including materials). I think it would loo pretty sweet with transparent acrylic and nice stainless steel spacers.
edit:
Ok, so my diagram didn't work very well, use your imagination!