I would have never guessed, but if you google for a PIC based eeprom programmer you can find kits and pre-built programmers on amazon. I'd give you the direct URL but amazon's are huge and probably contain personal info. Try this as a starting point:
http://www.lmgtfy.com/?q=amazon+pic+%20eeprom+programmer+usb-good luck
Edit: added later...
Yes the kits are probably not open source (or, maybe they are??). But the kit I found was under $50. It would be hard to create your own for less than that. Even if you had all the parts (as you say) already. This based on a PCB run of a few boards costing more than $50.
Edit: added later yet...
D'oh, sorry, a closer look and I see that only some of the hits are eeprom programmers. And none I see are kits. Ok, fine, I see how this works, now to make up I've actually got to find this mythical project somewhere...