I just built a desktop trackball ccontroller, and I didn't use a mounting plate either... maybe this isn't exactly what you have in mind, but maybe it'll give you an idea. I used carriage bolts and routed a recess in 3/4 oak.
I actually ordered the Happ Mounting plate before deciding on the recess... as much as I love the TB the mounting plate wasn't nearly as nice as I would think it should be, especially for how much it costs... Seeing the mounting posts on the thing I would tend to belive, like SirPoonga pointed out, that they would break easily.
Good luck in whatever you decide.
Stein
http://webpages.charter.net/mjellis1/btw the carriage bolt heads never get in my way on my TB
