Doesn't help you with the reversible bolt handle I'm afraid, but the Yugo SKS (M59/66), which I mentioned earlier, has a gas valve that can be shut off for grenade launching. This makes it a straight-pull 7.62x39. I'm pretty sure you can get a kit to convert it to take AK mags. Not sure how hard it would be to add a left-side bolt handle.

For a left-hand pull, you could convert a Steyr M95 to 7.62 and adapt it to a box mag, something like Lancaster did with his amazing Carcano carbine project, but using the AK mag instead of the CZ527. I've seen a Carcano converted that way. Switching a straight-pull bolt to LH is simply a cut-and-weld proposition. There was a Ross M-10 sporter with just such a mod up for auction recently. I've got pics of both rifles.

Update: I just checked out some pics of the M59/66 online. The left side of the bolt appears to be completely accessible, and only lacking the charging handle as is mounted on the right side. I can't speak with certainty without having one in my hand, but it looks very much to me from the photos that a left-side charging handle would be an easy addition. Anyone who's able to take advantage of suppressor technology would find the closed-bolt option would lead to better noise suppression. For a Cold War bullet hose, this rifle is getting more interesting by the minute. Not that it's going to replace the Ross or Brno on my favourites list, but in a post-apocalyptic Mad Max world, I think I'd rather pack an M59/66 than a black rifle. Apparently, I'm a traditionalist, even in my "assault rifles".