in both Oblivion and Skyrim ive heard of a few named bandit clans/faction

would you like to see more of that?

actually having min factions that could even end up fighting each other kind of like how the goblins in Oblivion would.

but what kind of banners would bandits use?

any ideas ... aside from skulls and crossbones (thats pirates)

Not really, it seems really pointless and wouldn't really be useful, especially since most bandit clans usually used the name of their hideout as their name.