Themed supermarket/outlet stores: good idea or excellent idea not?

I work a boring job. In retail. And sometimes I get to wondering (in my boredom, which is considerable) if it might be more interesting, or more appealing to the clientèle, or in any other way worthwhile, for us to pick a theme and seriously apply it.
Preferably a theme that lets us have pikes. You can tolerate a lot if you have a good pike handy.

Think RenFaire-Mart. Or Ninja-Mart. That sort of thing.