Ah! I found a pic of some Granatelli brand valve covers and they looked REAL similar to mine. So I did a search on this thread for "Granatelli", and sure enough, I made note of when Aaron Scott put them on the car and noted that they were, in fact, made by Granatelli. So I'll shoot them an email to see if I can get replacement gaskets from them.
As for replacing the valve covers, that won't be so easy, since Aaron had had a connection welded onto the passenger side one to connect a filtered air baffle so excess pressure in the engine during boost could escape in a controlled manner. Not to mention that it appears that replacements for the Granatelli brand have a $700 price tag on them.
Sure would feel stupid to have to replace them just because I couldn't find replacement gaskets. I would likely have to figure out how to make the darn gaskets myself.