I have two entities, Phone and Model. A Model is a cell phone model (eg BlackBerry Curve), and a Phone is a carrier model (Verizon BlackBerry Curve).

I want them both to contain pricing data (a PriceData entity).
I'm thinking they should both implements a Priceable interface that defines methods to get data necessary for price research. I'm not quite sure though. Phone and Model do not inherit from each other though, and I want to keep it that way if possible.

You can probably use a Table per subclass aka joined-subclass strategy. So both Phone and model will inherit from Priceable interface but they wont have any inheritance b/w each other.

Also the tables for Phone and Model remains different.