Miller Brewing has utilized stainless kegs with a black rubberized coating. Designed to protect the keg itself. The material acts as an insulator. Disadvantages are if the keg is warm, it takes quite awile to cool down and they are expensive to repair.
Miller Lite is a 2.6 volume product. At 38 F @ sea level, 14 PSIG should be adequate.
Scott Zuhse, Instructor
Micro Matic Dispense Institute