That's a wonderful idea. I learned French while working summer jobs. It wasn't through an exchange program, but they were still three- or four-month stints I spent immersed in French in Quebec. Similarly, some of my francophone colleagues learned English while working summers jobs in Toronto and going to university.
I discovered that, under the current exchange system, it's easier for a teacher from Ontario to take part in an exchange with a teacher from Australia than with a teacher from Quebec. Under that program, the teachers switch jobs and homes for a year. Likewise, it's much easier for a teacher from Quebec to go on the same kind of exchange with a teacher from France than one from Ontario. I think it would be worthwhile to explore those opportunities. A lot of things would be possible if we changed our approach.