I drove for Schneider Transport years ago, COE tractors back then weighed just over 14,000#s. Specked out a new 2012 Mack CXU613 Day Cab once for grain hauling , 14,875 lbs. M7 405Hp Mack engine, 12sp TMD12AO transmission. Single fuel tank. Super Single tires. Specked a Wilson trailer as well, weight was 8,160 #;s. This will allow for 1000 bu./56lb. legal payload.
You can still get them light and the price is not that crazy (lol). Did the ROI on both tractor and trailer, yearly savings will pay driver's wages.
Still have the build sheets for both tractor & trailer if you want them