Hi, I too was looking into this some time ago. A lot of people use an "écrivain public" (a kind of ghostwriter) and there are a few set up here and there. The niche in the market is that it's non-existant for people requiring text in well written English.
You could check out the ones around Suisse Romande and see if they have a need for an English writer. It's better to share a potential customer in a non-competitive area (since not the same language) than not being able to offer full service.
Kind regards