I think having a matching set with be totally cool. Dan, in your circumstances because your tug is a darker color, I think you'd be much happier doing as Ches mentioned...a stripe or some sort of accent. Otherwise the trailer is liable to absorb heat and you may be very uncomfortable in the hot summer sun.
This is one of my favorite tug/tow combinations from last year's Oregon Gathering. It's a 1954 Ford F-100 pulling a Casita
. That's Tweety Bird on the side...there's another one on the front and the owners had used the same yellow as accents inside the shower area and throughout the inside of the trailer.