Probably a Tapco T-6 is your best bet. While some of the black rifle crowd has mixed opinions on Tapco, their SKS stock is pretty good and gives you a similar feel to the AR platform. The AK mag capbility of the SKS-M offers some great advantages as well.
TAPCO® INTRAFUSE®
I had long considered doing and SKS-M + Tapco T-6 + Tech sites or maybe even a scout mounted red-dot as a nice battle rifle, but instead put the same $$$ into a budget build AR.
I do have a T-6 stock on my current Yugo SKS and have been very pleased with it. I've also had some of the other non-fixed lenght stocks and think this is the best one out there.
Alternatively, you could try to make your own side or underfolder, but that would tie up some serious $$$ and require some good fab skills.
Bylooking at your stock, you have a good pistol grip hold on your rifle....I'd save the time and money and just duracoat the stock black.....you might be able to shave a few inches off the end of the butt stock and finish it niceley....I wouldn't mess with that rifle too much, she looks good, u should invest in mags and ammo!