I've only seen them offered once or twice. Same source as the Falks. $1600 was going rate if I remember correctly, but have heard smaller offered for under $1K.
We just need to get someone to go down there and send back a few dozen. Thought we were getting closer to having them available but the whole gold rush thing down there sounds like it killed any chance of it.
At least we know we can get stuff here alive from that source, so if they ever do pop up again we know how the whole transhipping process works.
If you can't find males for them I'd be tracking down the nicest Marble male you can get your hands on..... Should look pretty close to the real thing.