Maybe I'm crazy (I'm certainly Mad ;)) but when I read this - "Steve Purcell came up with the concept for Stinky herself; he originally wanted her to be a mermaid, but they couldn't figure out how to make that work within the context of the diner, so the concession is that her apron is made out of fish scales." in the GameTap preview, I immediately started to think of how Stinky could have been a mermaid and still have fitted into the context of a diner. What can I say, it seemed like a challenge to me.
Anyway, I can see the dilema - if the diner is a land-based setting then Stinky is going to be flapping about without any water to swim in and if it's a water based setting, all the customers are going to have to swim which doesn't exactly lend itself to a particularly comfortable eating environment. The solution? - A location that is a combination of the two. I could go in to length explaining how this would work, but I've drawn a diagram instead which should make sense of it (note: diagram is roughly drawn so the rooms are a bit askew. Just imagine them as being rectangular in shape if this was a real scenario.)
Actually, the only thing that I think might be a bit confusing is the raising platform. Basically this would be a platform set into the floor of the diner, on the side of the pool and ajacent to the diner's tables. When Stinky swims up to the side and puts the tray with the food on to the platform, it raises to the level that the table is at and all the customers have to do is take it from the platform (at which point the platform lowers into the floor again).
Hope that all makes sense. Yes, I know this is all completely pointless as it's not going to be in the game like this but I just thought it was a fun creative challenge. If anyone else has any alternative ideas of how you could have a mermaid in a diner setting, feel free to share.