I’m going with the light box within a box design. I just finished my light box (which I made out of MDF board) and am in the process of soldering my white back light LEDs together and putting them in place. I have not decided yet on the kind of wood I want to use for the outer box or where I will get it. I may just use nice wood flooring on top of plywood....not sure yet. For LCD DSI you’ll want to use 4 layers to your “screen”. Top to bottom, you’ll want protective acrylic, endlighten acrylic, LCD panel and then the support acrylic. You may choose to put a diffuser between the support acrylic and LCD, but that is personal preference. The endlighten acrylic needs IR leds secured around it’s edges to produce the IR light for the cameras. I went with 5 meters of 850nm SMD5050 IR LEDs for the endlighten and 5 meters of white SMD5050 LEDs for my back light. I am using 2 PS3 cams with Peau CS mounts and 1.7 Theia lenses in Peau acrylic boxes. You’ll need a computer (or just the parts depending on your design). The carpentry materials will be different on how you build your box. Everyone does theirs differently. I really like I(make)tuchmyslf setup, and loosely based my table layout on his. However, they are not the same. One example is I created a false bottom on my table and have the PC components underneath (2 cams allowed for the extra space) where he has his around the sides. There is not right or wrong design, only designs that work and designs that do not work. Mine is still in progress, but once it is done I will put up pics of everything.
By the time I am all done, it might have been slightly cheaper to go with a IR touch frame, but I wouldn’t have as many touch points and I would not get all the DIY fun/experience. The bigger the screen, the more expensive everything gets. you’ll need bigger sheets of acrylic, more LEDs and you’ll need to build a bigger box (i.e. more materials which equals more $). Shop around......and do it often. I wasn’t planing on buying power tools to build my table, but now I own a jigsaw and sander, lol. Look everywhere for your parts. I’ve used Peau Productions, Amazon, Newegg, Ebay, a local acrylic shop (TAP Plastics), Home Depot, Sears, Acrylite-shop.com (for endlighten and protective acrylic) and a few other smaller websites for my materials and parts and I am not done yet.
The best recommendation I have is do a lot of searching and reading on these forums before you buy anything. Even after planning everything out, I will still go slightly over budget.
If you have any other ?’s, feel free to ask.