I've heard of players who do it (i think there was a guy in SF conservatory a few years back, but i never actually saw him). I don't think there is a way of playing the bass that is "right", there's only bad, good, and better approaches, and they vary widely from one player to the next. On the other hand, section string playing is a different story - you try to get the same sound concept in the same part of the bow with the same articulation as your principal player, etc. and there is a pretty rigid philosophy behind it with uniformity as a fundamental element. Also worth noting is the fact that i really don't think a violinist or cellist could ever get into a professional orchestra if they played backwards. Even if the issue is only the visual aspect of it (and to a large extent i think that is the issue) it's still a problem to enough people that playing lefty could serve as an unnecessary handicap at the professional level.
On the other hand, if you can do it without violating the philosophy of section string playing, then do it by all means. If it's the only way you know how to play, then of course you should play the way you know. If you are just deciding which way you want to play, just go with the traditional set-up. If left handed seems to offer some advantage, just know that the advantage is very short term and the disadvantages are long term. It's awkward any way you slice it for a pretty long while, lefty righty french german you name it. The only thing worse would be deciding later on to switch because of the logistical problems of fitting into a section or finding a suitable bass.
