You may want compare the ride height of locomotives equipped with those trucks to what you're proposing to build. Last time I checked, road locomotive trucks were substantially bigger than anything you'd find under the typical steeplecab. (same goes for MTH subway/trolley trucks)
I've been looking around for some sort of low-floor power truck that I could use to power one of those "City Liner" toy LRV's. Closest thing I could find without involving Q-Car products came up just short of 'O' scale.
There are power trucks from K-Line's trolleys or speeders that might be a better option. Recent SuperStreets vehicles with adjustable wheelbases are another possibility, and I was told at this past York that the power trucks for the WBB 44-tonner may also become available as parts independent of the rest of the loco.
---PCJ