I too look for nice 1:48 vehicles. So far my attempts are:
The tractor trailer in the H&H Feed Mill bay is is a Lionel that is claimed to be O-scale. Also pictured are two Menard panel vans, also claimed as O-scale (or 1:48). The tractor seems a little small in comparison to the panel vans.
For comparison effect, I positioned a 1:43 Ford truck (I don't know the year) between two O-scale pickup trucks. The black one is a 1953 Ford F100 and the red one is a 1948 Ford F1. Both I ordered from Diecast Direct from their 2018 Christmas Catalog. The two and a half pages of trucks was called "Railroad Truck Series Maintenance Trucks". Nearly every railroad was represented. All trucks claimed to be O-scale. They were mostly Ford, but there were a few Chevy and GMC trucks.