Buy a part not in the iFixit Store?

While doing a hard drive (HD) replacement on my 20" iMac, I damaged the temperature sensor which is attached to the HD. It is a small board, less than 1"-by-1", thermally bonded to the HD. The iMac works fine now, except the HD fan is always on, which is very annoying.

Is there some way to buy this part, even though it does not appear in your store? You seem to have access to Mac parts (including motherboards), does that same source also provide what I'm looking for? Even a scavenged part would be fine for me.

Hoping for the best. This is a great site.