Depending on where you're wanting to have the rental, you might find some information on the website of the community's website. For example, the place we visit in Graubunden, Vals, has an extensive list of holiday rentals that are not found in homegate.

I'd suggest contacting a few places directly and seeing if they might be open to renting a place out for a year. You're most likely to find this in an apartment building with a few apartments (rather than a single flat available) , as many folks renting out have guests that will have weekends reserved years in advance.