PSC chips aren't rare, in fact all of the kits you listed are probably using PSC chips. If you want a kit that can do 1000MHz, buy a kit that is binned for 1000MHz, or you'll end up with a kit that can only do 1000MHz at very relaxed timings or higher voltage. Check some reviews and tests of the kits rated 800MHz 6-8-6, that's actually a mediocre bin for PSC, and binning is very important with those chips.