I know what you mean about wanting an earlier cub. I think the 47-53 tractors with the ribbed hood, wire front grill, and exhaust stack were the best looking cubs. I wanna say that they modeled a very early cub for the first edition, since it had those round "Cub" logos on the front doglegs. The problem with that toy is that I had to pay $75 for it, and it is hard to find another one. Plus, when you pay $75 for it, you don't want to cut it up or modify it.
Why Ertl never went back to the exhaust stack, or ribbed hood for any future releases is beyond me, except to think that they broke the molds after the special edition run. Stupid move, if you ask me. I doubt we will see new tooling of the old style cub. Seeing a precision Farmall Cub is probably wishful thinking, as well. Perhaps Spec-Cast will do a high-detail version of it, someday. They just did a High-detail John Deere L with a very very nicely done sickle bar mower.
Will we see a cub like that? Here's to hoping!
quick edit: If you look on the engine and the hydraulic unit of the 56-58 cub, close up with a magnifying glass, you find the numbers 251341R2 and 351981R1 What those numbers come to in an IH parts book, I don't know, but they really took a LOT of time to sneak those details into the tractor.