Well, you would probably be perfectly happy with a Bronica - many, many people make pictures light years ahead of anything I will ever make with Bronicas. Its just a case of bang for the buck, faultless reliability and unlimited ability to expand your system. The RB has metered prisms - which I would not waste my money on, as I wouldn't on any MF system of this type - it also has motor wind backs available (although the one I saw is 6x8), abiity to shoot any 120 - based format you choose (short of 6x9) and lenses from old to brand new are available, depending on your needs vs budget.
Example: a ProS body, with a 120 back and WLF and a 90 mm k/l lens for $280, on eBay. All in better than average shape, lens looked pristine. As far as metering goes, I would put my faith in a Pentax spotmeter instead of a battery dependant metering prism anyway.
For a more short term solution you could try working with a TLR or RF - I know its not your ideal, and yes, they have their limitations, but it may be a nice, sub - $100 way to dip your toes in the MF pool. But given the prices of systems that are precisely what you want, the savings are not that significant and to my way of thinking, you may as well just go for it.
Peter.