My wife chose our particular motorhome because it was trimmed in light colors and had big windows for lots of light. There are other color schemes for the same model (or its Winnebago twin) that are darker.
I think you'll find most manufacturers offer alternative color schemes. What you see at any given show is what the local dealers are ordering, and they usually make that choice based on experience with buyer preferences.
No options on number of windows and sizes, but there is a lot of variation brand to brand. Bigger windows are more expensive, budget priced RVs tend to get fewer, smaller windows.