They'd still slaughter Bane.
Bane is an inferior duelist, slower, and far less skilled than Ventress. If the match was Qui Gon Jinn and TPM Kenobi he might get a few rounds though. Ventress can dodge his lightning, absorb his TK with a force shield, and dance around him while Savage sends him flying with TK.
My tiering differs from Carthage's a fair amount.
I'm with Newguy on 'probably not.' I don't think it'll be a slaughter, but it is two strong foes who work well together. Maybe if Bane gets lucky, but he's not as overpowering in the force as Sids was, and Sids' force powers is the main reason he was able to handle them like he did. Somewhat lower dueling at the same time, and it's a rough situation.