If you're not getting many replies to this it could be because Mac hardware options have gotten kinda crappy for this sort of thing lately.
The gfx card in the current Mac Pro is not that fast for the price, the iMacs come with a screen and the integrated graphics in the Mini Mac are getting a bit old.
Add to this that OSX still doesn't support some (by now not even that recent) OpenGL features and it all looks a bit sad..