Instead of using FTIR as a method for vision based multitouch, you can also use a method of flooding the acrylic surface from the back with an IR illuminator like Microsoft does with their Surface. We created our own IR illuminator by bundling a certain amount of IR leds close to eachother. We did some testing with this. We had some very strange results. Instead of the blobs turning up very white and bright, they were black. This was probably because of the Astralit, which we temporarily use as a projection screen. We had this idea that maybe it was because of the silicone rubber, but we did some tests and it seemed that it wasn't the silicone rubber that caused this strange behaviour. We're going to extend our research, next week.
We also quickly assembled two small multitouch prototypes for two of our software engineers in Stockholm, so they can continue developing our software.
The budget software engineer kits (DIY) and the assembled ones, that we are going to sell, will be somehow be similiar to these models, but of course with a slightly different design.
We will start selling multitouch hardware in our webshop in the near future. If you want to keep posted about this matter, please feel free to leave your email address on the following page: http://www.multitouch.nl/contact.php