I have yet to actually paint a runner up a flight of stairs.
I LOVE the idea though and can only imagine all of the incredible possibilities!
Check these ideas out-
The ORANGE really pops! I like the band along the top of the baseboard too! Nice and graphic!
This Simple BLUE defines the staircase- I like when I see one knows when to stop. Very chic.
Stripes in varying widths and shades of grey and blue is classic and casual, SORT OF BEACHY.