French parts aren't difficult to find. I came across a NIB Campagnolo pista BB with french cups for a song, along with a number of other french BBs and headsets for my builds. Sourcing these parts has become even more affordable with Velo-Orange's sealed french BB set.
A quick spin of sandpaper will allow standard stems to pass the locknut. Reference Sheldon Brown's page on French bikes.
You simply have to do some online searching, or call up some local stores. That said, if you have the room, keeping the Moto geared and picking up a Kilo could be a nice option.