Anybody know where one could find a flat, oldsmobile "badge" for an aftermarket alloy wheel?

depends on the size of the emblem, etc...I bought a set of smaller stick on Olds emblems to replace the missing Cragar emblems in my SS/T's at a swap meet...I'm sure theres someplace online that sells them as well, its just a matter of finding them...

You can get replacement stickers for the old 70's style SSII wheels center caps. I saw some on EvilBay made of some kind of plastic material, they had the black background and the red rocket in the middle. These were aftermarket items, as I recall the originals were on very thin metal disks which were glued onto the top of the center cap.

I was thinking about pulling the rockets off of my current hubcaps, if I could do it without mass destruction...

Replacement stickers for the SSII's and SSIII's are available from Year One, Original Parts Group, Fusick, and others like them. They will work fine if they are the right diameter.