I think I'm going to go with the dual sided pedals that are SPD on one side and take mtb shoes, and flat on the other so you can wear regular shoes if you so desire. The mtb shoes have a recessed cleat and you can walk in them.

Gotta admit though, I never thought of indoor shoes. Heck, I've only spent one day a week of the last 10 yrs at different indoor facilities.......................