I'm sorry I don't but it's a lot of fun (or used to be*) on Townhall.com., they allow EVERYBODY. *The trolls have dropped from about 30 to the regulars (5 or so).
Seems like there are more conservatives than liberals posting comments at salon these days.
Also, often, surprisingly, at SFGate, which is the San Francisco Chronicle’s web site.
The Yahoo Answers politics section can be great fun.