i imagine that it could be possible, like "non-existent" crates/urns/containers you carry around (so you have the same interface as if activating a container). or multiple inventory screens?
wait... you have the stuff already sorted via the tabs in your inventory (magic, apparel, weapons, ...)
as much as i liked the bags of holding in BG-series, they were a bit unrealistic
well, at least apart from the true bag of holding, which is magical. but the others could definitely hold too much for next to zero weight.
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=6907 - not quite what you had in mind i think...
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=1193 - sounds interesting (don't know the mod)
well that's about anything i found (keywords: the aforementioned bags of holding, "containers", "holding", "carry", ...)