I realised after seeing other interlocking designs that it would be possible to print a toy car with no support (as long as you were willing to put in a bit of effort breaking a wheel enclosure away from the wheel). As a least-work compromise, this model uses minimal support (printer-program generated, to be removed) connecting the wheels to the axle surrounds.

I have yet to print this fully, but there have been a few iterations to increase wheel/body space and reduce overhang.