It doesn't sound like money is going to be much of a barrier for you but a Koni-Omega is the best bang for the buck. Lens quality is supposed to be on par with Hasselblad and film flatness is unparalleled. They are ugly and bulky, cheap and uncommon. If a Mamiya 7 is on your list I wouldn't expect the Koni to be but take a look regardless. Interchangeable lenses and backs.