I'm in what seems to be a challenging position. For some reason I can't find many contractors in my area (North Shore MA) to quote geothermal for me. Over the course of about 4 months I've found 2 for which I have actually received quotes. Several have indicated I'm not in their service area and I have one coming next week to hopefully bid on the job.

Of the two who have quoted, only one is in my ballpark for a 3 or 4-ton system. The problem is that the one in my ballpark (sort of) only has experience with vertical loops. I have a lot of land so I'm hoping to find someone willing to do horizontal loops mainly because my expectation is that it should be cheaper than drilling for wells. As a result, the HVAC guy is relying on the company that referred me to him to design the loops. They of course don't want to put much effort in loop design until I commit to something, but I won't commit until I can establish a cost for horizontal loops, which means I need a design to bring to an excavator. I'm getting rough estimates that range from 3 150ft trenches to as many as 8 or 9 depending on soil conditions. This of course is useless for getting bids from excavators. Is loop design really this complex? Does anyone know some good contractors in my area?

You need software to help, for example:

http://www.geoconnectionsinc.com/

are you looking at one 3/4 ton heat pump? If so you shouldn't much more than 1 or 2 trenches at 150' . I have 5 for my 4.5 ton heat pump.

Sorry I meant 3 or 4 ton system

you need to know the heating and cooling loads, then you can design the loop field

Manual j is around 42k. planning on tightening up house to bring down to 36k.