im a lefty too, but i play right handed. but i guess it is within oneself on which way to start.
even a right handed guy can play a left handed bass. anyone can play either left or right.
it's just the use of your brains. and how they work.
well just like what exin had said, do you really really need a lefty bass?. or is it just you wanna stand out from the rest?.
well by using a right handed you can get more varieties of bass no doubt about that.
it's up to the individual, because at the end of the day, you just gotta ask yourself whether did you enjoy bass playing on a lefty or a righty.
what matters most, just do what you love.