I kind of looks like the face of the pulley they use on the idler pulley for a smog delete kit. Does it have grooves for a serpantine belt or a groove for a v-belt?
I love the 2 door Tahoes thats why I ask, that and I am board with my F-150. Bump for a nice looking Tahoe! Have you thought about eBay, They seem to fetch pretty good money on there, atleast they did when I was looking for one:)