Rich,
There shouldn't be any problem, really, with just splitting your bass signal with a simple y-connection. If what you want is some separation, sonically - ie an amp on either side of a stage, this can work. Unless you are looking for something more complicated, like stereo output, then you are probably fine. But then, you would be fine with two cabs as well, as long as you were watchful of the impedance issues. As Bob suggests (inferentially, by his deft Socratic method), it all depends on what you want, and of course the result will be dependant on the amps you are using.
Rick