I'd like to recommend that you post this survey over at the Starship Modeler forum as well. I guarentee you'll get some good info there. That's not to say that this forum doesn't give good info. It's just that Starship Modeler's web forum focuses on the very sort of thing this thread is all about.
BTW, I agree with the others. I think it's a great idea but anything larger than 12 inches should be vacu-formed. A resin model tht size would be too heavy (even if it's hollow-cast I think) not to mention very expensive.
I'd consider buying an 18" multimedia kit (main hull vacform, details and greeblies resin or whitemetal/PE) but only if it's under $100. I actually think that might be feasible too.