Here are a couple layouts I've designed.
The first one is my own layout. It is an HO Scale New England based freelance layout, which operates CSX, Amtrak, NECR, CSOR, Pan Am, and a few others. My layout is 8'10" wide and 17'6" long.
This next one is my buddy Ryan's. It is also a New England based layout, although his is N scale. He operates the same railroads as me, except his is themed in the early 90's. The layout is 3'6" by 5'.
PHOTO COMING SOON
Next up we have another HO scale layout. This layout is 8' by 10' with a single track mainline and no curves tighter than 36" radius. The owner didn't specify the region or era, and only gave me a few basic things to work with.