[son of a gun]

Does anyone know what type of receiver you need to build a legal Krinkov? any other insight on Krinkov's would be appreciated also.

[Destructo6]

IIRC, the Krink uses a standard AK receiver.

Handguards, barrel, gas tube, and gas piston are the oddballs.

[MLC]

It depends on how seriously you want to follow the Krinkov form and how much you want to spend. I think that these are your options.
You could legally build a post ban receiver Krinkov religiously following the
US parts count and having a fixed stock and without NFA paperwork an extension of the barrel bringing it to the legal 16". A post-ban SBR is doable but you can't have a flash hider and are limited by the US made parts count.
If you were to buy a pre(import)ban rifle, you could build a folding stock Krinkov with the same barrel extension or a long permanently attached flash hider.
With the proper NFA paperwork and tax stamps you could have a SBR(short barreled rifle) Krinkov built on a pre-ban receiver with the appropriate barrel and any muzzle device.
Finally, I think that with a class 2 FFL you could reconstruct a torch cut Krinkov(as many parts kits are) legally but it would not be transferrrable.
Forgot one thing, if you have the jingle you could buy a class 3 AK and hae a smith tear it down and rebuild it with the Kinkov parts.
Good luck, they look like bad little pieces of machinery.
If there were a range within reason that allowed bullet hoses I'd be on that track as well.