Yeah, the IdeaBlade.Common.EntityModel occupies a sort of limbo between DevForce and IdeaBlade.CAB/Cabana. It's necessary for IdeaBlade.CAB-based applications, but doesn't depend on any CAB or IdeaBlade.CAB stuff, so it can be moved to a straight DevForce application.
If your DevForce application doesn't use CAB, you could try changing your BaseEntity in that model to inherit directly from Entity. I've never tried this, so I can't guarantee that it would work.
Bill J.