As I recall, the major locomotive manufacturers had plans for a 2-8-8-2 for the ET&WNC, D&RGW, and RGS as well as an ET&WNC 2-6-6-0 (and I think a C&S version also). There were a few proposals also for a narrow gauge 2-6-6-2.
The D&RGW 2-8-8-2 was provided with a new and a K-36 like make-over - new running gear, old boiler from SG steam.
The only one that was ever produced for the US (I think) were the two 2-6-6-2t's of the Uintah and Sumpter valley (after URY folded).
I think most of the 2-8-8-2's were outside frame. There are several concept drawings, like you show here, on the Existing World wide steam page.
I think that there was even a NG Garrett proposed for the D&RGW but that may be incorrect.
Doug vV