Yes, you could buy a 200A, but wouldn't it likely need some work, too? I would not let that 140B slip away from you! It's a very special piano. If you still have any interest in fixing it, a couple of suggestions:
-- Call Retrolinear to discuss your piano's issues. You've not been specific about what you find lacking in the piano's performance, but it's possible you could mail your amp to them, and that any action/regulation work necessary could be done by an acoustic piano tech in your area, using the Wurli manual as a guide.
-- I will send you by personal message contact info for a vintage keys tech located about 90 minutes from Charlotte. I have never used him for Wurli work, but I am well-acquainted with him, and have no hesitation in recommending him for his integrity, and his skills on other instruments. He does service Wurlis, both electronically and mechanically. You may want to call him and discuss what he could do for you.
By the way, the reeds on the 140B are the same as the Model 200 reeds, so replacing them would not be a problem.
Alan