Well, Lionel doesn't have a small speed control board, at least not using TMCC or Legacy. Perhaps the new LC+ 2.0 board with TMCC could fit in some of these. I think the Trackmobile is a lost cause, they even had to tether the caps to fit it in.
This is the board that is sold through ERR as the Mini Commander 2 for small motorized units.
The smallest thing I've put cruise into is the RMT BEEP. Getting cruise and Railsounds with custom lighting in that one was a challenge, never mind something the size of a speeder or Trackmobile!
MTH has the 44-Ton locomotive with cruise, etc. I have one of the MTH models and a Williams that I converted to TMCC with cruise and sound.