Don't buy anything unless you get a response. Even then I wouldn't buy it, it's just too expensive for what it is. Also, all the pictures you see on that site are generated by a computer, they're not pictures of the actual product. So I don't trust it at all.
I bought my SLI-M last year, it's a great bit of kit. Took a while for the guy who does the coding stuff to support Windows 7. And he doesn't totally work on LFS, but there is enough support for it and he will keep updating it.
Sadly I bought it a week before the release of the SLI-Pro, and I wish I sent my SLI-M back and paid for an upgrade.
I now have it mounted in a nice box, with the help of my dad hehe.
I mounted it in the same place as these videos show, but the setup of the wheel and distance of the pedals makes it hard to pay attention to the read outs. I now have it setup infront of my screen so it's under the wheel in lfs.
Hoping once I finish uni I can try and make a custom wheel or addon to the g25, so I can fit the SLI-M onto it
That website is where you get the firmware updates and Apps that work with the SLI devices. There is also a forum section where EK "the guy who makes the stuff" Posts updates, answers questions and helps us guys out.
I think you should be able to find a blueprint there, or you could always photograph the SLI-Pro and use that to work out a box design.