i put on a wald chainguard last night that i picked up from a parts bin for 5 bucks. terrible mounting, but it guess it works. I've been running a pretty wide chainline though, i'll probably have to move the chainring on the inside of my double cranks.
velo orange makes a fully covered chainguard. she ain't too cheap though:
http://www.velo-orange.com/postch.html