Don't rule out outdoor venues: parks, large gazebos, fields with benches.
I know it's not mainstream, but it's not unreasonable to host a competition outside. If you can get your hands on the right equipment (tables, chairs, microphone, etc) and confirm that the weather won't be crummy, then outdoor competitions are highly desirable. I know a lot of people that love the ambient sunlight that speedsolving out of doors provides.
We had a CT cube meetup and unofficial competition that took place in a small park at some picnic tables, and I personally really liked the venue.