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), Crew cab, 4x4, Standard box, Bose system, leveled by prev. owner, Cognito UCA kit w/ shock extenders, custom paint, leather, tie rod sleeves, 300W Rockford Fosgate Amp & 2 JL 8" subs, Bilstein 5100 shocks