Is the Bachpersonn actually based on the Penn P-70, or is it "looks more than enough like it"? Similar to the RR paired window coach, I have heard and read that they are based on a Baltimore and Ohio coach. The MT is based on a B&O coach. Still, all three look alike, except that the Bachmann does have four wheel trucks (as did the P-70, or most of them, at least). B&O did have some standard coaches that had four wheel trucks, most of which were in commuter service in Washington, Baltimore and Pittsburgh.
Do you find the B-mann factory knuckle coupler unsatisfactory, or do you just prefer the MT? I have one of the B-mann B&O coaches and find the B-mann coupler acceptable. It is good to know that the MT conversion is not difficult, as that external spring on the B-mann IS a weak point.
Nice job on the details on the Penn coach.