People have made driveable vehicle mods for New Vegas, check it out:
https://www.youtube.com/watch?v=7t48Hrq5Sfc#t=215
Should be timestamped, if timestamp doesn't work skip to about 3:30.
It's a total laugh-out-loud disaster as the bike smashes into things that don't exist, disappears at random, twists around at impossible angles, inexplicably glides through signposts and presumably eventually crashes the game. There was an airship mod for Skyrim with similarly bizarre psychedelic results.
If modders can't work a driveable vehicle into Gamebryo/Creation, then I doubt Bethesda's own developers can.