We've already proven we don't have to use local ska bands to fill the "local" slot on ska shows. We have and will continue to use non-ska local bands on local ska shows, when of course there are some solid out-of-town ska bands available for any particular date. Hobo Slobo was the main local draw on that Taj Motel Trio show and they did exactly what we expect a local band to do (turnout was hurt more by the last minute nature of the show). Joey Driscoll and Aiyana Catori have worked well too for local draw and they aren't ska either.
Unless we get a kind of local all-star ska band together that can play a lot (which would be a very cool goal), we won't use any local bands more than once a month and out-of-town bands far less than that.
Don't worry about that part. The real question is:
How much ska is too much? 
I'm addicted to good ska and would happily see bands every week (
a la Bluebeat Lounge) if they were mixed in with other good acts (local and not).
I guess that I'm really wondering if anyone else feels that way ...