Hi, I don't suppose that it will save your grid getting fried, but air heat pumps are now being built which can cope with New England Temperatures.
Here is a Canadian company:
http://www.gotohallowell.com/technical.html
Hallowell International: Technical Data

The Japanese, surprise surprise, are also moving fast on this with pumps using carbon dioxide:
http://www.r744.com/news/news_ida210.php
Coming soon: ITOMIC Eco-cute heat pump - R744.com News

I believe that it may be some time before those are available in the States though.
If you think of getting one the guy to talk to is Here in Halifax - I think he recommends a Fuji model.

Hi Dave,

Just so they don't go moving the international boundary markers on our account, Hallowell is an American company based in Bangor, Maine. And you were close -- Fujitsu is the manufacturer of ductless heat pumps I consider to be among the very best in the industry.

Cheers,
Paul

Darn! You've uncovered our nefarious British Imperialist plot to 'readjust' the boundary!

Dup post