i have been in the r/c hobby for about 32yrs now and have been in the r/c trucks for awhile now and its true ..the companies cannot build every truck out there because as mentioned before ..who will buy it and the cost of the rights to put there name on it would make these kits unreachable to lots of people..i can give you a perfect example of stupid money..i have a real 1985 Kenworth W900B and for a plain set of mudflaps for the front fenders behind the front wheels are about $50pr ..to get the same style set with the name Kenworth on it around $180pr ..just because the name is on it ..you cannot even build something that you are selling and call it a registered trademark name without paying some sort of royalties to the owner of that registered name .look around this site here ..you will see tons of builds that would and could qualify to fullfill your need for a W900 and all built by scratchbuilt and machine made parts
and not to mention the process of 3d parts makes it easier to have what you want in record time without the hassle of scratchbuilding