Yesterday I was speaking with a friend who is also returning to the hobby, same as me. He mentioned a project he did a long time ago, building an SD40-2 carbody hoods and cab from styrene and Cannon & Co parts. This was circa 2004-2006.
Does Cannon & Co still make the doors, grilles, cab, etc required to do this project again? Intent is to build Milwaukee and Soo Line SD40-2’s and WC SD45’s, if possible. I know Scaletrains and others make highly-detailed and accurate models of these, but he wants to build from scratch. And Scaletrains refuses to offer a WC version of their SD45. Why, don’t know, but you cannot deny they were a solid fixture in 1990’s Wisconsin and the Upper Midwest. They made a WC SDL-39, so they know they have a WC market, but the email I sent them a few months ago about a WC SD45 was replied as “thank you for your inquiry but we have no plans to offer a WC version at this time” 
He will likely use a Kato frame and motor, unless something different is recommended. Will be DCC with LokSound decoders and lighting (headlamps and ground/step lights).