Thanks everyone for your input.
Ouch....the thought of creating a "false cab" does indeed sound daunting. Little more work then I had planned.
I tried an asset that I have based on the RW2 version which was distributed with the old model files but I found little things like the wipers not working, etc which was disappointing. As well, I wasn't overly impressed at all with the textures. The most viable option I think is the DLC Santa Fe SD40-2 but I was hoping to keep the reskin available for everyone using a default based asset. Therefore, I'm thinking of leaning to the newer RW3 version to get the full advantage of the the new model even though there is some prototypical differences but it will be more usable for users because its default and not relying on DLC. I have a couple child items I have to create (roof overhangs) that should make it look different enough. The lights and ditch lights won't be right but actually, it won't be any different then the CN SD40-2 DLC and I haven't seen too many complaints about the inconsistencies there. It kind of reminds me of my HO modelling days and trying to paint a stock Athearn SD40-2 to look CN.
Anyways, I'll post updates as I begin working on my reskin project.
Thanks again for all your input.