From the research I did, there is not.
I ended up going with the iSimple solution which gives me a drop out of one of my storage compartments to hook into the base of my iphone. The sound quality is really good and to use it I have to put the system to the "RSE" input. Ran me like $140 installed.
Bought 6/16/11: 2006 Chevy Silverado 2500HD, 6.6L Diesel (LBZ), CCSB, Bose system, leather. Southern Comfort Conversions edition. Includes: Custom faded two tone paint job, leveling kit (cranked T-bars), 18" chrome wheels, aftermarket interior trim, billet grille, remote start, wheel to wheel steps, and Line X installed. I upgraded to: Cognito UCA kit w/ shock extenders and Bilstien 5100's, Tie rod sleeves, 300W Rockford Fosgate Amp & 2 JL 8" subs behind rear seat, Tinted front windows to match, BakFlip F1 Tonneau cover, Reese 15k 5th wheel hitch & Prodigy brake controller added