The definitive answer to "Who plays Richardson on Deadwood?"
I'd be willing to bet, that if he were to shave the beard and get a haircut, you wouldn't recognize him.
If you are a casting agent, hire him, I'd like to see him in a role other than Ricardson.
Just a few roles I think he might be good in without changing a thing...
The villain in a Scooby Doo movie
A Viet Nam vet both then and now
President George W. Bush w/ a Beard (sorry Ralph)
A performance Artist (but not like this crazy freak).