.41 Special isn't a SAAMI approved cartridge, but there is brass available from Starline, and loads available for it in various places on the web.
No. M57 and M58 (and later, the M657) is all you get. There is a M520, a fixed-sight .357 Magnum with a tapered barrel and shrouded extractor rod; the originals are rare birds, a LE special order that fell through and then sold to the public.
Thank you for the info.

Model 520.

I had both the M58 and the M520. I thought they made a nice pair.
I sold the M520 last year.