after reading this thread the other day, and moving my cabinet...my agp card popped out of the slot for the first time.  i used standard little brass threaded motherboard stands that come with just about all PC cases.  i drilled some holes in the wood, threaded in those inserts, and then screwed the motherboard in just like it was in a pc case.  this didn't put it up high enough to allow the video card to go the entire way into the slot, so i had to bend the bottom part of the video card bracket to make it fit, so i just bent it at 90 degrees and drilled a hole in it.  then i installed another motherboard stand and screws the card to it...i is rock solid now...i'll take pics later if anyone needs them.