I am currently making a yo yo bed cover (size undetermined at this time). I think a yo yo bed runner would be beautiful. Mine is scrappy so will go with any decor, and a scrappy bed runner could be used the same way. These are very time consuming and not everyone's cup of tea. However, after I saw a friend's, I fell in love with the look and just had to do one.
For a traditional look, you could blend a bed runner color with the comforter, spread, or whatever you have on the bed. Would really dress up a bed & your room. You will receive many oohs & aahs!!!!!!!!!!!!