I've ordered their kit and installed it, it was fairly easy. I also order some scrap acrylic and bulk heads and made a "kit" as well. As for cutting slots in the glass might be a little tricky- You would have to take the brace off and you might able to use a diamond blade on a handheld grinder, though I'd get kinda irritated if a "tooth" broke off.
It might be possible to make a acrylic box for the outside of the tank and use a bulkhead of two to connect through the tank. Then run the drain through the bottom of the box. I think a member did that for a seahorse tank.
Edit: Boy there were a lot of mights in the last post! Here is that thread I mentioned
http://www.atlantareefclub.org/forums/showthread.php?t=75612