While thinking about voltage conversions, i got an idea to modify the charge pump that would enable bidirectional current flow. Picture bellow, sorry for non standard schematics.

The idea is to swap diodes with controlled switches, mosfets for example. Instead of driving capacitor strings, you drive switches that equalize the voltages of connected capacitors.
Driving of mosfets could be done with another capacitor string or optoisolated gate drivers.
The whole circuit works as voltage equilizer of capacitors. You can load the 1xV point, and supply the voltage at 4xV, or vice versa. The string can be longer, power can be loaded or applied at any point.

Has anybody seen such circuits already? Could not find it on internet, yet it seems quite useful.
Seems quite great for transformer replacement if you switch from AC to DC grid. I was always more of a DC guy.