where is all the SBP mags at?

so, ive been keeping an eye on the wheels for sale section but I just have not been able to find any SBP slotted aluminum rims on here

whats going on...or people hoarding them?

I would love to get a set in 15X8s or maybe even some big-n-smalls, 14X7 and 15X8?

the car is a 71 duster, with an 8 3/4 rear end so I'm not sure what sizes and backspacing works, but I'm guessing 8 inches with 4.5 backspacing is about max?