With some creative circuit board hackery you could expose only the motors to 2s and the rest to 1s or regulated 5v.
You'd have to cut the original motor +v traces and wire them to 2s directly, then wire a small regulator (ideally switching/buck, but whether the increased efficiency would offset the weight I don't know) to power everything else on the board.
How easy or hard this would be depends on the PCB layout. On the E010 FC it would be pretty straightforward.
This does assume that the FETs are rated for enough voltage, of course. If not you'd have to replace them too.
The key is that the (admittedly very few) boards I've looked at so far so their motor control on the - side of the motors with N channel MOSFETs. Boards to switch positive instead and use P channel MOSFETs can't do what I listed above. Not without more surgery.