About where have the .41's gone.. Good question. I own two of them in Blackhawk. I bought one NIB many years ago at a gun show.. think it was somewhere in the early '80's.. Still have it in unfired condition. I picked up my shooter shortly before that used at a local gunshop for a nice price..somewhere in the $250 range, if I remember right. You still see them once in awhile at some gun shows, but not nearly as often as you run into the .357's and 44 Mags. The one I call my "shooter" is deadly accurate at 50 yds. if I do my part.
As far as ammo goes, I bought a bunch of new brass and dies a long time ago, and I roll my own. I would have to go downstairs and check, but I'm sure I probably have 200 - 300 loaded up now, and a box or two of empty brass that needs loaded. I haven't been doing anywhere near as much shooting as I used to, and need to get back on the range and get the rust knocked off.
Back to the availability of Rugers or any other handguns in .41 Mag, last time I checked on GunBroker there were some available. However, as you know, you can't hold them in your hand, visually inspect as you would like, check for cylinder slop, throat erosion, etc, etc. The best you can hope for is have the seller agree to a 3-day inspection for your satisfaction, and free return shipping if isn't up to your expectations. Most honest sellers won't have a problem with that. I have personally bought quite a few long guns and handguns thru GunBroker, and only remember having trouble with one sale but it got resolved favorably. Good luck in your quest..