WoW has a mod that does just that Mother. It does come in handy at times, as it's an option to your regular bags and not a replacement.
As far as AIOI, I've used it and ended up getting rid of it because I like using my bags for separating items. Such as, one bag for all collectables, another or quest items, another for sellable items and so on.
However, you can pretty much achieve the same thing in EQ2 by using the following mod:
http://www.eq2interface.com/download...fo.php?id=4379
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.