Try Allegheny Arsenal
they seem to be only one's at the moment that I can see. Most of the other sites that I was looking at sourcing a kit from last year have gone out of stock. The good news is that, from everything I've heard, their kits are great, are pretty easy rewelds, and come with the rear receiver pieces unlike most of the other parts kits, hence they charge a bit more over a standard parts kit without the rear.
Your only other option right now is gunbroker which you would have to be patient with and watch since there are some over inflated prices out there.