I am planning to build a work shop in Canada where winters are quite cold. I want to keep it above freezing (at least 5deg C) at all times. I am considering insulating the foundation walls to below the frost level and super insulating the building with the idea that the ground will radiate heat up through the floor and heat the shop. Supplimental heat will be used for warmer temperatures when the shop is in use. Does anyone have any information or experience with this?

If you search under superinsulated on the web you'll find a lot. I have a couple of books dealing with the subject too, but their titles do not come to mind right now.

Here is a good website for an introduction,

http://www.ext.colostate.edu/pubs/consumer/09936.html

The frost line only means it stays at 0 C or above in the coldest years. You may want to look at going deeper, or some of my reading suggests going out. Even if you don't reach the goal of no heat needed, the more insulation you use, the less heat it will be. No matter how well you insulate, you will still lose some heat. Heat from deep in the ground will be slow to replace it. I haven't seen much about heat pipes lately. Just a sealed tube with a easily volatilized liquid. The vapors rise carrying heat with them. The liquid condenses and drops down to the bottom. Might see what you can find.