You know your business better than I, but maybe it would be good to ask a question. Is it actually a farm tractor you want? I think that construction has it's own equipment that is specialized in doing that type work. Construction equipment is likely to get the work done faster and with lower maintenance costs than a more general-purpose tractor.
The idea may be to use 3ph implements to reduce the number of separate machines required. I seem to recall a question about putting a 3ph on a skid steer. I think the answer was either that it could be done fairly easily or there was a factory option from some manufacturer.