My dream shop would belong to me. I have the perfect place picked out, it is cozy, but 3 floors, so 3rd floor would be all set up for classes. It would easiily accomodate up to 30 people with their own machines. (No having to figure out anyone else's tension problems)!
2nd floor for backings, battings, used machines (no high pressure sales, if you like a machine buy it), a sewing machine repairman on site who knows and can fix ALL and several long arms for customers to rent.
The first floor would be for the eye candy, fabrics, books and patterns.
But I really have not given this much thought.