engine oil leak

[rednekkin1013]

After 2500 miles I am 2-3 quarts low on oil. the truck has been doing this for the past 10,000 miles. I have fixed the o-rings on the turbo pedestal and my rear main is dry. I have been told WITHOUT a diagnosis that is most likely the HPOP...... The truck is a 2000 7.3 ford diesel......I have 2 questions:

1)could it be anything else

2) if it ends up being the oil pump what is my best option.... can they be cheaply rebuilt or would I have to buy new?

If I buy new it will be upgraded from stock where is the best place to look