@Jon Cannon @NitroMenace @maxdman @CarCrusher
I hope to not come across as a know it all but if anyone cares for some learning:
The original CRD chassis was based off Adam Anderson's Taz chassis (which was a "inhouse" chassis built at the digger shop). Depending on your POV, there have been 3-4 revisions to Carroll's chassis since it has debuted. Basically all of the revisions were to remove problematic areas that were over engineered and make them simplistic to fix or repair.
FELD Inhouse chassis's have had alot of revisions since the original crop of chassis's. Mostly to stuff you cannot really see by eye (tube sizing and wall thickness). Bracing philosophy changed over the years but the relative shape has remained untouched.
Once Paul left FELD he started his own metal fab shop, he has built the current Fullboar and Over Bored chassis (I have photos of another possible chassis he has built but I have not seen anything that matches it).
Eddie Mikjas is also a name that has surfaced offering inhouse clones (he has a few distinct traits in bracing vs FELD or Paul). Krazy Train, Black Pearl, Hurricane Force and Bad Company 2 are Eddie's work currently running, with another chassis sitting at Vaters shop unbuilt (you can see it in Mikeys video blogs) .
Realistically they are all basically the same as they are based off of a similar wheelbase
If you want a visual (I do not have a Eddie or Paul uploaded on there but you can atleast get the idea)
Gen 1 CRD https://p3d.in/RMURA