Sounds fun but not easy to set up I think, or maintain either. Buying and spending the stuff is a shade different from creating and managing one as a whole, from what I know of it.
Also reputation wise, that could cause the value of the coin to sink dramatically (the market as a whole is batshit as is), due to a wide variety of reasons that are probably also hard to foresee. Best to just use regular Bitcoin my guy, and donate to the farms through other means.