I've started with two McKeen sets in 1/29-scale (if the results  will be satisfying, maybe a preliminary practice for a model in 1.6" -scale).

First set will be a 70' McKeen motor coach car with knife-shaped nose; it will receive a 31' baggage trailer. I had SP's #45 with it's trailer in mind first, but made the mistake with the knife-nose, which wasn't Harriman design - so I'll look for fitting prototype...maybe UP's #25, which came from ATSF or V&T's #22 w/o the trailer.

Currently under construction is UP's M-10005 'City of Denver' in 1.7"-scale ´(running on 7 1/4" tracks).

Kind of a step-by-step visualization of the construction:

Frame and driveline

Basic subconstruction of the shell - the nose-core is shaped of foam and will be removed later

First of my really big streamliners (1.5"-scale) was the (in-)famous 'Aerotrain', GM's contribution during the light-weight-trainmania of the mid-50's.

building the shell - glass-fiber layers on subconstructions (fiber-board, steel tubes etc.)

shell and chassis disassembled with a look into driveline-setup

Two samples of the famous Borden's butterdish milk tank cars - in 1"-scale

UP F-7 in 1"-scale built from a Maxitrak-kit upgraded with additional details

Amtrak F40PH Phase III in 1"-Scale

and mated to a MHC (used as an operator's car)

Well, not absolutely 'streamlined' but in it's tradition:

Krauss Maffei's KM4000 CC in 1" -scale

starting with a rough glass-fiber shell

reshaping and adding cut-outs

more details

Maybe my studies and job - both dealing mainly with aerodynamics, streamlining etc. - caused my interest in streamlined rolling stock. So I scratchbuilt several prototypes of the 30's to late 50's (ok, some exceptions going into the 70's) in larger scales.