If the truck beds just hafta be white, I'd do as Simon suggests and simply repaint the cabs, rather than wasting a lot of time and money trying to find an exact match.
Wayne
Weathering can make wonders to harmonize colours... You could also repaint the cab. Or keep trying to match the white. Posting a picture might help - some guys on this forum are pretty good at telling what colours are involved in the mix.
Simon
another place to look is at a auto parts store, spray cans of touch up paint come in a wide assortment of colors.
Are you talking white, as the color, or White, the truck manufacturer?
Maybe take the cab and chassie with you to the stores in your area that have the biggest selection of spray cans, and see if you can find something close enough.
Even a hobby shop that just does planes and RC vehicles will have a good selection of paint. Or a Hobby Lobby, Michaels, and even JoAnn Fabrics.
I understand Krylon brand spray paint is good on plastic.
Anybody that has found that perfect match, probably did it the same way.
Good luck!
Mike.
My You Tube
I have four Walthers Scenemasters white trucks that I am replacing the purchased truck beds with different 3-D printer truck beds. However, my multiple attempts to get the new truck bed to match the cab have not been successful. Can anyone share a paint brand and color number that has proven successful?