The three prinipal makers, IIRC, have been Armalite-Costa Mesa, Charter Arms, and Survival Arms-Henry. The ones currenty being marketed are the Henrys. Myself, I like the Chater Arms variant better, because the wrist of the stock on the Survival/Henry seems like it doesn't have enough angle, and I can't get my nose down far enough to see the sights. YMMV. They do make a scope mount, but it always seemed to lose the cool of folding into the stock that way. All parts will interchange between all models except the early Armalites, and most of those will too. (I forget which ones don't.) So if you find a Charter with a shot-out barrel, a Henry barrel should fit.
The 30-round mags that use the long ribbon spring work fairly well, until you split the case. I never had any others to try, but I know they're out there.
You're making me really wish I had never horse-traded off my last one--