CZ 457 a.k.a. "Legos of Rimfire"

Hey, anyone out there into CZ rifles? I am putting together a new NRL 22 rifle, and I think I might go with CZ 457. Apparently, you can change out barrels, calibers, magazine wells, stocks, all very easily. Unfortunately, they appear to be pretty popular because everywhere I look the “minisets” are sold out–CZ’s own website, Bud’s gun shop, and others all seem to be out of them. Should I just pick a different platform? Are they always sold out like this, or how quickly does stock usually recover? Are there other outlets to buy parts from that I’m not seeing?