I don't think the 45k figure to drive 49 steel pilings 53 feet into the ground sounds unreasonable at all. Have you priced steel lately? I'm betting just the materials for that kind of job would be 15-20k.

My house is built on standard treated class B wood pilings. I have 26 pilings and they are imbedded to a depth of 15-20 feet. As I recall it cost about 11K for materials and labor.