I use these:
http://www.fortexfortiflex.com/roundfeeders.html

The rubber is heavy and solid, dishwasher safe. It's designed to be used by horses, so it's really durable. My crazy Lab has yet to destroy his. Cut a notch in the side and turn upside down. Heavy, snug, and dark. My girls love them.

They cost me about $3.50 at the pet store, either in the dog or horse section.