> KSTJ, WTIL Story, and UK Chill Out were pretty hard to find.  I still don’t have a copy of
> Eternity Project One on CD, and I’ve only seen about 2 or 3 of these turn up for sale.
 
I'm hardly an authoritative person to get respectable input on this matter but for my two bits:
 
I proudly own the first three, so they can't possibly be that rare!  :)  KSTJ I don't think I've ever seen come up for sale except for the one time when I bought it.  WTILS shows up on ebay from time to time, just keep looking, as does Eternity on CD but it's too rich for me.
 
Based solely on stuff I've seen or haven't seen come up for sale (and again these are for proper commercial releases), I'd say some of the rarest are the Disco 2000 cd single for Uptight, the french (i think it was) cd single for TARDIS which has all six mixes (but it sounds crap so don't waste your time), and the OZ History of the JAMs.  I searched for that particular one for YEARS and finally scored one.
 
-paul