All in one bag.

[FloridaFringe]

You can pretty much achieve this by using the right mod and setting it up accordingly. One such mod would be: Link

Set to Frame Only so that there is no Drag / Title box or Close X and the bags will become completely title-less with just the slots showing. Then simply align them up against each other and use the Open All Bags keybind. When open, all the bags will look as if they are one single bag.