Right now we don't have support for RGBW Z-Wave bulbs and we're in fact waiting for the Sigma Designs to send out samples for an RGBW bulb so we can implement support for it, as it's based on a new Z-Wave device class and they promised everyone would get a bulb.
Looking at the Aeon Labs bulb, don't expect great Z-Wave range, as they seem to be using a chip antenna and they don't have the best of range, although they're incredibly tiny.
Don't expect these to be cheap, the Linear bulb is $35+ and having talked to them at CES, their rep claimed that GE, Cree and the other guys aren't making any money on their bulbs... which simply isn't true, but hey.