http://austinsportsgear.com/products/index.php#extreme
http://www.safesports.com/inline.html
http://www.mountainboardshop.com/craspadpadsh.html
http://theinsideedge.tripod.com/#Protective
I have the Austin Extreme Shorts, which work well. Don't ask me how I know...
Check out the Austin Garage Sale. Last year's model for only $25! Thanks to Piggyslayer for the tip on the Austin shorts.