Desert Proven
Observer
There are 3 that come to mind. KORE, Carli, and Thuren. They publish info on coils for 3500's, but you might find that they have coils that work on the 5500 as well. If you've already talked to them, then I apologize. Historically, the coil bucket on the dodge has been the same size throughout the range and there were larger (taller), stiffer coils for heavier duty applications. I admit I'm not as well versed on the newer, 5500 series however..