SRJB69,
We have made a transfer pump from a large car/truck air con compressor. Don't know model off the top of my head.
Made a base with belt drive & single phase motor. Works ok, still heavy though.
Compressors cheap, maybe $300.
I think clients should be pushed to install there own, in plant room at least. Bock have small ammonia compressors for $2-3000.