James,
Those names are all good choices. Along that same line you could use Stoney Mountain, the Duluth Kid, Rebel Rassler...
Some people like the fanciful concoctions like Will Ketchum described, some like using the name of a character in an Old West of B Western movie, and some like an obscure (or not so obscure) name of a real-life person from the Old West.
Some people only pick a name as a name and don't dress to it, others have as much fun dressing to their name as they do actually shooting.
I got lucky and the name I wanted and got was not taken.
The best/fastest way to find out if a name is taken is to call the SASS office. They are very hekpful, and you will know immediately.
By the way... WELCOME to the world of CAS!