Hello Scot. I double checked with the folks at Air Lift and they actually do offer one air bag kit for the 2005 Chevy C4500 Kodiak, the Air Lift LoadLifter 5000 Air Helper Springs # AL57292. They do list a few specific models of the 4500 that it will fit, and I have included a screenshot of their fitment chart below.
Aside from this one kit, everything else we offer for the 4500 will be the Timbren bump stops like you mentioned. The Timbrens work great for support when you are towing,... view full answer...