I just wanted to say thank you for all the posts and recommendations in this thread!! After a lot of research I ordered 20787107 w/bluetooth chip already installed off E-Bay for under $200. I was a little worried because it was listed as "removed out of an 08-10 SAAB" but the cross references matched to other trucks and other E-bay sales. So, I took a chance and it WORKS! The OnStar light is now out (not red) and when I push the blue button it says the account is inactive. I don't plan on using OnStar anyway but I figured I will give it a whirl tomorrow. The truck is being dropped at the dealer so they can install the backup camera I had them toss in with the deal so if there is any programming to be done it will all be done at the same time.
Anyway, tickled pink that bluetooth works! Thank you, thank you, thank you!!
-Trip
2008 GMC Sierra SLT