Just came across this thread. I had posted this idea elsewhere but it appears there might be more interest on this topic here.
This all came about several years ago when I was rummaging thru my scrap wood pile. I noticed odd shapes and had that eureka moment.
Basically here are two pictures - the end result and some product pictures taken today. Todays pictures are the result of rummaging thru my scrap wood pile.
These are all readily available stock size lumber; 1x4, 1x6, 2x2, 2x4, 2x6 - you get the idea. The height, width and arrangement are completely up to you. Roof angles, bump outs, windows, doors whatever you want. All you need to do is clad the lumber forms with your sheet goods; wood, styrene, metal.
31" long. Starting at the left; 1x6 (horizontal) with 1x2 bump out, cut up 1x4 enclosed stairwell. Loading dock in front. Next building is 1x6 (vertical) with sloped roof. Next is an elevator tower (2x2) with sloped roof. Right of that is 1/4" plywood with sloped roof. (Trying to get as much recess to hold the 3 storage tanks). The next and thickest section is the pitched roof (2x6) with sloped roof (1x6) attached in front. The end is a 1x6 with roof access.
These are todays scrap box examples and quick arrangement that started it all;
Sloped roofs on the left; 1/4", 3x4, 2x4. Carrier sheet. Couple of elevator towers with connecting walkway. 2x6 with severe roof angle. The small piece of wood under the 2x6 shows the shadow (interest) that you create by bumping one piece out a bit more.
You could probably rearrange todays scrap pieces and form most of the finished example model.
Could be a city high rise flat. Just more scrap; 1x6 vertical with sloped 2x4 in front, 1x4 horizontal, high rise 1x6 with elevator shaft (old 2x2 deck spindle), 1x8 horizontal.