My Ultra High Tech Waterproof Cover

[Loupey]

I've used this a couple times, the last time was an hour in a steady drizzle with nary a drop underneath.

Gander Mountain sells a jacket/pants rainsuit set for $9.99. Snip off the pant legs to your desired length and secure with a rubber band at the end of lens (better if you use a lens hood). The other end (knee end) fits neatly over a 30D without battery grip - although a grip would probably still fit - I just don't have one to know for sure.

Cut a hole in the bottom for the tripod mount. The thinness of the PVC allows good tactile feel of all the knobs, AF/IS switches, and focus/zoom rings.