custom payment terms for supporter

This is a suggestion for supporter term options.. I had to modify the code to be able to offer only a single month recurring subscription option.. I think it would be good for super admins to be able to add the options that make sense for their site.. it would be good to have the option to configure each option as well.. both duration and recurring or single option and be able to offer both at the same time both recurring and single payments. Right now it is very limiting to only be able to offer 3 "canned" options (1 month 3month 12 month) and have to pick between recurring or single..