Hi Anston,
None of the converters you suggest would be appropriate, because as I stated in my question, I need to synchronize the converter to an external frequency source.
I don't actually care much about output ripple per se as I am post-regulating. When I said I'm looking for "low noise", I meant low noise coupled into the rest of the board--I should have been more clear. And it is important to keep the noise synced to my clock.
Although the Inverting Buck-Boost topology is Buck-Boost by your technical definition, from the standpoint of the converter it is Buck only, so I believe that most of your Buck converters can be used in this topology. I'm trying to select the best one that meets my requirements of external sync and low emitted noise.