I've seen 3 or 4 the pre-Remington Marlin 1894c's for sale over the last half year, but they get snapped up immediately. I don't participate in CAS, but one shortcoming of the 1894c is the 9 rd capacity (in 357) --- you have to do a bit of work on the magazine to fit 10 rds. The 1894 Cowboys (20" and 24") have sufficient capacity, but are likely even harder to find than the 1894c's.
While I have an older 1894c, which I like very much, if your budget allows, I would look at the new Winchester 1892s. They're quite a few more dollars than the Marlin, but from all accounts, they're an extremely well-made rifle.