To my knowledge, there has never been a snoot nose SD40-2 produced in O scale (besides in those very expensive brass models). These are the same as a standard SD40-2 but the nose is noticeably longer, designed to accommodate equipment for "Locotrol" which was an early way to control DPU's.
The first is a snoot nose SD40-2, compared to a regular SD40-2 in the second picture
How much interest would there be if a model of this were to be produced? There's definitely plenty of road names to paint them in and most of them are still running around today.