@James A. the GCs I've spoken to have been experienced guys who deal with both investors and homeowners generally. One of them freely admitted that he could get it done for just over half the cost of what he'd charge me HAH! That kind of honesty is commendable (even if annoying).
But when I say full gut and rehab I'm talking: taring everything down to the studs, updating plumbing and electrical throughout, probably upgrading the panel, adding duct work for heating and cooling, new mechanicals (boiler, A/C, etc) , hardwood floors, new kitchen, new dry wall and insulation, paint, finish work, etc. So if you need less than that done then you'll spend less per square foot obviously.
Now again I think this is highly dependent on what you know and who you have relationships with. So it almost certainly can be done for less that what I stated originally. In fact I really want someone to tell me I'm completely full of crap! That way I can reduce my estimates, increase my MAO and stand a better chance of buying something in this hot market.