Once you get a preamp to drive them, it doesn't really make much sense to me versus a cab optimized for bass and a micro head. They are typically not voiced optimally for bass guitar (especially up top... usually way to bright with no horn attenuator), and they are typically quite heavy.
IMO, if you are looking for a bit of a more smooth, more hi fi voicing, a full range, multiway cab like the Audiokinesis Thunderchild or LDS 12/6/1 and a small micro head would probably be the way to go.
IMO there, and only a couple IME situations playing out of powered monitor and PA speakers in a music store setting.... so 'take it with a grain of salt rule applies'
