a router is also nice to cut plexi with.
i used the router attachment for my dremel and was able to cut out circle holes for my fans just fine, infact it was better than a holesaw i think and didnt melt it too much aslong as i moved fast :)
otherwise the best way is to us the scoring method :)
scoring definately works the best, but my epoxy didn't hold up so now i'm using L-brackets with bolts in conjunction to the epoxy so far so good
Long Shot,, but Does anyone happen to have a backup of my pictures that I had on this post originally? :) I see someone had asked me for a zip-file of them. I know it's been more than 8 years,, but hey, it's worth a shot.