Ted, I believe Paul's cabeese ARE modified from Aristo's cabeese. I know paul does a lot of work to make things look right.
I too am getting ready to do a group of modified Aristo cabeese to be correct for the GN version. The Aristo long caboose is based on a 25 foot design, GN's standard is based on a 30 foot design. So not only will I have to be lowering the caboose, but making it longer too AND change the cupola to a centered side window and smaller end windows. On this early attempt, X-274 shows features of the next ones I'll be doing, but they just need to be longer. Correct Bettendorf Barber trucks will round out this modification.
A lot of special hand made details went into this model. I expect more to go on the next ones.
I got about a dozen REA cabeese I've been hording over the years, so that may yield about 5-6 kitbashed models.
I figure if I do them all at the same time like a production line, it won't take as long and be easier too. 2 of these
will be special cabeese and will need a special cupola. I'll start a thread later when I start the project.
Now GN Did have some of the 25 footers like Aristo, but they were wood side and the cupola was like X-274.
One thing I noticed on Aristo's models, most are based on a NE design. This makes it more work for those of us
who model western roads.