Not sure if this fits the bill or whether you've already considered and discounted it, but... Have you thought of a Mamiya C330 interchangeable lens TLR (or one of its predecessors)?
Lenses (especially the black ones) are top notch, build quality is "hockey puck", handling is good on a tripod, otherwise okay, weight is erm... best thought of in geological terms(!), TLR so no DoF preview...
Not for everyone, but I love it ('cept for the weight halfway up a Munro...)