I did not do this but have seen trucks painted to match the 5th wheel. In my opinion - wow, way cool.
I know a person (meet him at an RV Park) that has a F550 painted to match his Newmar 5er. It is one good looking rig and competes with the expensive motorhomes for best looking rig in the park. His truck has one of those fancy western conversions with as hauler bed. I googled the conversion and it turns out to be a $25k conversion...yikes. I forget the conversion but it was something like
'Western Star'. It probably included the custom paint.
A cheaper way that I saw was matching stripes added to the truck that match the trailer.
I guess if I won the lottery I would think about matching paints between the truck and 5er. But until then I will tough it out with mis-matched colors...oh well.