I sent a couple of emails about Wedgits and disability issues to the folks at Wedgits maker ImagAbility and they responded by sending me some stuff to try, including this "Building Board," presumably because they thought it would make for stabler building, reducing the effects of clumsiness.
It does indeed, and I recommend it for anyone with small motor problems, disability related or otherwise.
This particular structure would have been impossible without the board, but it can also be used to make simpler structures easier and less frustrating, including most of the designs on the cards (the exceptions should be quickly obvious, from how the lowest level of Wedgits is arranged).
[11/02/05] I found this picture when I was uploading the Roy Toy pictures I took today, and decided to simply append it to the Wedgits post it belongs to, rather than create a new post. It shows maybe a little better than the original picture how the center section is suspended well above the building board. Plus it has kinda nifty backlighting. The one with Archie has its own charm though. :)