This has been a great forum for ideas. This and small-cabin certainly have the best forms on this topic. I wanted to add my contributions with regards to details about small cabins in Quebec, Canada. Because it is all in French I though I would share what I have found out.
I have done most of my research for Val-Des-Monts, Quebec which is a small municipality about 35 min north of Ottawa, Ontario in Canada. I believe it is applicable more globally in Quebec as a cursory look at other municipalities in the region (La Peche, Pontiac, Val-des-bois) seems to show similar laws.
It is important to understand that the province of Quebec is special in that the official language is French. Most municipalities only function in French and all bylaws are in French. Translate.google.com will become your friend if you do not speak or read French.
The major finding from my research is that small cabins as many of you describe here are NOT permitted to be built on empty land. In Val-des-Monts the only structure that you can build without a permit is a gazebo of 10 square meters (107 sq feet) and I am sure if you plumb, insulate and put a wood stove they will make you take it down as it does not fit the definition of a gazebo.
Environmental regulations are strict. You may not build closer than 15 meters (49 feet) to any body of water (creek, river, pond, lake). You may not cut down trees within this 15 meters except for a 5 meter (16 feet) window for views from your cabin to the water.
If you want to build a building that requires a permit, there are minimum size laws. For a single story structure it must be a minimum of 60 square meters (645 sq ft) with a ground floor of a minimum 50 square meters (538 sq ft) (so I assume you must add a 10 sq meter loft). If it is 2 floors it must be 100 sq m (1076 sq feet) on the 2 floors. This sucks as those sizes are no longer cabins but more like small houses or cottages. The only exception is if you have 20 hectares (49 acres) then you are allowed to build a ďcampĒ where the building may not be LARGER than 55 square meters (592 square feet).
However, once you have an approved building on your lot you are allowed smaller outbuildings. Make note that only one of those outbuildings is allowed to be habitable and is only permitted to have 1 bedroom.
So you can see that if you want small cabins in Quebec you are better off trying to find an established building that is grandfathered. These structures are often smaller (eg. Real cabins, 16íx20í, ect), and are built very close to or nearly on the water. The ideal situation is a falling apart structure that allows you to rebuild in the same footprint without paying the full cost for the structure.
As an aside, I guess to increase tax revenues as well as to prevent squatters, you are not permitted to have a recreational vehicle (motor home, tent-trailer, ect) on your empty lot. Not for a weekend, not even one night! So you are paying taxes but unless you want to tent you canít spend a weekend on your land! And for tenting, donít think about leaving a canvas wall tent up for the season either, I am sure they will make you take it down.
So I hope this helps my fellow Canadians who are wondering about what the regulations in Quebec are.
Iíve purchased a nice lot in the area because the price was too good to refuse. Unfortunately I bought before I had time to do all this research and I though I could toss up a little 10x12 structure that would make me happy. I donít have the budget for a 600 sq foot place right now but we will see in a year or 2.