A lot of these stretch models that I have seen simply split the frame and add additional tubing with the proper gusseting to make it whole again. Front and rear of the original frame are kept, keeping the original vin numbers.
Many original 6 cyl broncos running around that have been replaced with 8 cyl or more modern engines, hell even the smaller 4bt diesel engines.
I understand questioning the frame extension to a degree, but seems like your getting rather nit-picky on the rest..
I get the "stretched" idea, and I wasn't trying to nit pick on it. That wasn't the point. This (the Clydesdale) is similar to a Centurion. The Centurion is really not just a 4 door "Bronco". In spite of it's similar appearance, and the common reference by the FSB guys. And it is titled as such. In either case, it's no longer a "Bronco" when the body has been stretched and built on a "replacement" chassis that just happens to be an F250/F350 chassis. The Clydesdale is just an earlier version of a Centurion. The bottom line is that Ford never mass produced a four door early Bronco. But the body is inconsequential on a framed vehicle The difference (in my mind) is that builders are representing and titling them as "Broncos" when they really arent. That was (partially) the point in mentioning the engine. When the builders stick a Ford VIN from an early Bronco on a "replacement" frame, they are trading off the original Bronco. There is a difference between using a slightly modified original frame where the original VIN and CVIN are both in tact, and one that has a highly modified frame where some random margin of metal surrounding the original VIN is transferred to a replacement frame. ....or...someone reproduces the original VIN on a "replacement" frame. That is more than likely criminal.
On a different tangent, I would be worried about this would play out in the case of theft. If I sink a bunch of money into any vehicle, only to find out that the bones were stolen....I'd be pissed.
Bottom line in my mind having been through this......
1) The Clydesdale is only slightly more "Bronco" than mine. Mine is also built on a "replacement" frame. Aftermarket sheetmetal on the Clydesdale is no more "original" than fiberglass. I still have a warranty tag on my glove box door, and an original, albeit modified, Bronco dash. Probably a few more pieces that don't come to mind. If it would bother the Bronco community that I would maintain that mine is a "Bronco" (which it does indicate on my title) then it should also feel the same about the Clydesdale. It is/was not a Ford production vehicle......It's a self assembled fantasy creation.