I finally got the tower installed on my kegerator!
I got a power tool just for this project, called the Rotozip. It's a spiral saw; I'd never heard of one of these things before. It looks like (and apparently can be used as) a router. Very good control, once you get used to it. I'm sure I'll have many other uses for this thing.
I've also posted an album of the construction process.
The first beer on tap is an Extra Special Bitter.