Stripped receivers and complete lowers as well as complete AR style rifles are plentiful at local gun shows here. All seem to be selling very well too.
Buying the receiver and parts separately lets you avoid the $100 excise tax on complete guns and you get the parts exactly as you want, otherwise I don't see much point in having stripped receivers.
I got a CMMG stripped receiver for $110 at last weeks gun show.
I'm not stockpiling but I've three on hand right now (Stag, CMMG & Spikes) and parts on order to complete one. I still want a 16" fluted bull barrel, a 9mm, and the 7.62x39 upper and mags are on order. Lets me spread the cost out, and the receiver is the only part I can't get via UPS so if I see one at a good price at a show and have a little extra cash and future configuration in mind (.22 LR?) I'd possibly get another.
As I recall the '94 ban was ruled that if not assembled before the ban it had to be assembled in post ban configuration, however if you had pre-ban parts and a pre-ban serial receiver unless you did it in the presence of someone who'd rat you out, how could they ever prove when it was actually assembled? As I recall the price of flash hiders and bayonet lugs skyrocketed after the ban
Buying "pre-ban" parts post-ban was potentially trouble with regards to completing a receiver.
Obviously with the future availability of the parts for the configurations I want in doubt, I'm moving up my plans as much as possible.
--wally.