Hi,
Thompson Brothers had a plant in Peshtigo Wi, and also (for a while) in Cortland NY. The company had gone out of business and back in business several times, but I believe is gone again.
You can look at the following link at Dan Miller's site, which may help you identify it.
http://dragonflycanoe.com/id/index.html
Dan also sells a CD with historic Thompson Catalogs, which is fun to look at if you are into Thompson boats and canoes.
Thompson Brothers Boat company built a variety of canoes, but their most popular wood and canvas canoes seem to have been the Indian, Hiawatha and Ranger models. These canoes changed shape, and it seems, names over the years, but in general, the Indian had a long nose profile, and no half ribs, the Hiawatha had the same shape as the Indian, but with full size half ribs, and the Ranger had a more traditional stem profile, and lower sheer line. The Ranger was available in 15 to 17 foot lengths, the Indain 15 to 18 ft, and the Hiawatha 16 to 18 ft lengths. I have one of the original Thompson forms for the 18 foot Hiawatha model, you can check out my website to see if your canoe matches this model at:
http://www.geocities.com/mferwerd/Hiawatha.html
Some other Thompson related links are:
http://www.thompsondockside.com/
http://www.fiberglassics.com/thompson/
Best of luck with the canoe