I remember seeing these a LONG time ago. Are there any available anywhere? I also heard they had magazine issues. Was this ever fixed?

I think model1sales.com still sells uppers in that caliber.

Personally (of course ,you didn't ask for one ) but i'd just get an AK if i wanted a 7.62x39 rifle. Why not have 2 rifles instead of 1.5 rifles ? :)

Try model 1 and DPMS. You can get colts on gun broker but they are not cheap. My friend has a DPMS 7.62 upper it was real finicky about mags. I found 41 USA mags and we tried them all at the range and about 70% were perfect and the rest were jam-o-matics. Gun broker would be the best bet for mags also. As a note feed ramps on his upper looked like crap very rough lots of tooling chatter marks, could be part of the feeding problem. My RRA's ramps (223) looked like a mirror.
Good luck