It seems pin lock 2.5 and 3 gallon kegs are a bit rare. If you do find a Cornelius ball lock one I have some extra pin lock posts I would swap with you. Most pin lock 5 gal kegs are Spartanburg which have different posts which don't fit the 3 gal cornelius kegs, but I have the proper Cornelius posts if you do want to swap.
I have 2 I am looking to get rid of, pin lock, new gaskets. Was going to build a portable kegerator but decided to go with the keglove/5 gallon instead.
PM me if you are interested, I am in southern california.