There are some options but you may have to do a bit of fiddling with hands etc as there are not many grot driven vehicles as that's too cool a job for a grot.
Warboss in Mega Armour
Grot from squighog boyz
ShokkjumpDragsta, grot in the passenger seat.
Wazbom Blastajet very small gunner grot/snotling
Alternative option is to use some Gnoblar's with a grot headswap if you don't like there current heads or want them to fit in, the Scraplauncher has 2 Gnoblars turning a wooden wheel with handles.
Few bits from my own works where I've done a bit of cutting and moving arm positions to have a grot operating something