In your list you only have 5 repairs done to the engine. Waterpump is common around 100K, glow plugs and harness hit or miss around 100K, CPS is just when ever. As for the rear main are you sure it wasn't the boost boots leaking and just the oil seping out of them that made it appear the rear main was leaking? At least you don't have to worry about blowing headgaskts and EGR's.