Air Sealing of Electrical Boxes on exterior walls

It might be easier to look at using Icynene (sp) spray insulation and using regular boxes and wiring methods.

Someone had made nail-on boxes with a flanged gasket that sealed up on the back side of the drywall. Might have be a Canadien firm.

Check out this link.
http://www.lessco-airtight.com/

I think the route to go is the open cell spray foam insulation between the 2 x 4s. I would still want the 2" of foam board over the 2 x 4s to reduce thermal bridging. If the electrical boxes are not air sealed, this moves the air barrier to the spray foam. It would require sealing of the 2" foam board to the 2 x4 stud walls, which I should do anyway.

I appreciate the ideas for the other boxes and I will check them out at the store. At first glance they don't seem that much easier than sealing up a standard box. I will probably just stick with the standard surface mount boxes and not be so scrupulous about sealing. Thanks.

Okay I got it. The boxes mount on the surface of the drywall. I've done this before on a soundproofed room using 4 square boxes with RS covers. You just have to seal the little hole the NM wires comes through the drywall. I will check them out at the hardware store. I hope the wife goes for the aesthetics.