In my area, I have neighbors wanting to do what you proposed, but they're not allowed to put in mechanics (HVAC, water, sewage etc) due to zoning laws.

Talk with an attorney, but you might be able to file a "Mechanics Lien" for the work you have done on the house.Also, check with the laws of your state to see the legality, and monetary limits, of a verbal agreement.

My name is Connor Sullivan, I am a recent mechanical engineering grad and currently the wellhead manufacturing engineer for a up and coming oilfield company. 

Emphasis on the last 2 words -- priced correctly.

Its a savings mechanism.

It is basically an open space outside of the the mechanical/laundry room. 

One of the aspects that probably contributed to the triples failure is that they are a lot heavier with 3 panes of glass and I suspect that the mechanisms are the same as the 2 paned mechanics and not beefed up for the extra weight.Some earlier replacement windows were aluminum but today most are vinyl. 

I guess I kind of use it as a weeding out mechanism.

I don't bother with insisting they are stainless inside because the mechanicals wear out quicker then the inside.  

A unit that is sized too large for the amount of cubic space in your home will just cycle on and off more often, and that can be bad for the mechanical parts.