A visa that will allow me to be in the schengen zone for at least 1 year

I run a US social enterprise and need to be based near Geneva for more than 90 days for nonprofit consulting work. I could be based in either Switzerland or France. I'm open to starting a company in France but under the impression that this will take more time than I have. I need to have a visa in-hand by 12 Nov (when I'll likely hit the 90 day limit) and I can't be without my passport for more than 10 days at most between now and then. I'm a US citizen.