CNC Warrior and Bonesteel Arms folding M4 stock hinge
Bonesteel Arms and CNC Warrior are starting to sell their side folding mechanism that looks very similar to the TSD Combat Systems'. It is available with or without the mil-spec buffer tube. You have to provide the stock. Of course putting an M4 style stock on an AK is one of the worst things you can do for an AK purist, but if you like the adjustable length of pull and other things it provides this looks to be a really good option.