Re: Pmags all gone already??
They are out there...just SLOW DOWN, breathe, and calmly look around.
That said...prices are already climbing on mags at least at various places I've seen online and locally. The closest Cabelas to me had their PMAGs (standard, Gen II, non-windowed, 30-round mags) for $19 (regular price there is $14.99 which is still somewhat high). Looks like their online prices are still at that level though (and they are in stock if you get too desperate).
As for online sources...check with some of the Hide vendors before you stray too far in your search. Several different folks here have had PMAGs in different flavors for sale over the last month or so at competitive prices.