Richards does list 600's as special order 8 week lead time... I've gotten some nice wood & wood laminate stocks from them...
http://www.rifle-stocks.com/actions_available.htm
BTW my 600 had been refinished with a satin oil finish, & looked quite nice, even though it had a few "use bruises" the satin oil finish hides them alot better than the shiney laquer finishes...