[Rataxes]

Well, like I said before. backstab is one of the main reason why you want to dual to a mage, so you can take advantage of the Mislead + Backstab combo. A Swashbuckler completely misses out on this, and for a mage, the rather puny combat bonuses added by a low level Swashbuckler definitely doesn't outweigh that. That's why any other sort of thief is a better choice.

A Swashbuckler/Fighter would be more interesting, though ultimately, I think a pure Swashie or even a multiclassed Fighter/thief would be better off, and that without the pain of playing an extremely low lvl fighter for a while.