Mobilehome Electrical Distribution

I am a journeyman electrician with much industrial, commercial and residential experience, but no mobilehome experience. I am assistant manager of a mobilehome park of 192 units. Many services have been jumped to other services(before my time) because of main feeder open conductors(I think) All distribution wiring is underground feeders(direct burial cable, no conduit). 100amp 2 pole breakers from main distribution panel feed 4,6,8,? homes with 50amp mains. How many units can you put on 1-100amp main feeder? (main feeders are type UF 1/0 AL)(all units are double wide) Also, I need to change many pedestals but am having a hard time finding manufacturers(Milbank is the only one I found so far) any suggestions? Last, but not least, how do you normally ground these pedestals? I see the grounding conductor going down into the ground, but I see no trace of a ground rod. Any help would be greatly appreciated.

You would probably be better off asking this question over on the Electrical Contractor BB

Basically the answer is in NEC article 550, 240 and 220.