[lincpimp]

You could make an adapter to charge your 2 2s lipos as a 4s lipo, as long as your charger can handle 4s lipo. Not difficult, post a pic of the batteries, and a close up of the balance plugs. Brian's site can give you a wiring diagram to do it as well.

As far as a 4s pack broken up into 2 2s packs but factory wired as a 4s pack... I have never seen one. It would be easy enough to make a 4s pack into what you want, but I would need the chassis to get wire lengths correct.

A 4s2p pack has 8 cells total, 4 pairs of paralled cells that are arranged in series to achieve 4s. Probably not what you are looking for.