Aren't UBEC's just packaged voltage regulators?
A BEC would work for high-current voltage regulation, with perhaps one caveat: Some  cheaper BECs seem to have non-exemplary voltage regulation under load. 

This isn't just about current or inductive spikes, those actually get handled well because BECs are designed to run motors. The issue is more around sustained currents - the thermal protection kicks in quite harshly once things get warm.

This may be a good thing, since the BEC survives the heat easily... or it may not, if a combination of voltage sag and thermal current throttling under sustained load would kill your application. 

For the price of a BEC, it would be a worthwhile experiment.