Realized my Corvette brake master cylinder (non-boosted) will hit the Patrick's shifter on the Saginaw. Figured out that a '67 Ford Mustang disc/drum MC is narrower and will work, AND that an '87 Dodge D series pickup MC is even narrower and can be set up with two remote reservoirs instead of the modern looking plastic tank it comes with.
...still undecided which to go with tho.