As my focus is on the Santa Fe in the transition era, I know that I am already blessed with a variety of motive power. My wish list:
1. for Athearn Genesis (or Walthers):
GP7 (zebra stripes) with "torpedo tubes"
GP7B (zebra stripes)
It would seem logical that Athearn Genesis will produce these items at some point, but I would like to accelerate this process.
2. Smaller steam. At the moment, Santa Fe steam locomotiv models in "plastic" are models of large engines, such as 4-8-4, 2-10-2, and 2-10-4. BLI announced that they will produce a 4000 class 2-8-2, but this is still a relatively large Mikado. What about a "plastic" version of the arguably most common brass steam engine, the Santa Fe 1950 class 2-8-0?
3. Gas-electrics ("doodlebugs"). The "plastic" Bachmann version of the M.131 is generic and not a good representation of the prototype. The Hallmark brass versions are improved, the ones from Key are top notch. However, especially the latter carry a stiff price tag. It might be worthwhile for some company to explore the possibility to produce doodlebugs "in plastic", just as Rapido did for the RDCs.