I'm not going to release v3.0 of Memberlist until after UBB6 leaves beta. There are still some significant changes I'm pushing for regarding the public names, so I'm not going to spend any time coding it until close to the end of the month, when the beta should be in its final stage.
In general, don't expect anything but very minor hacks and bug fixes to be released while UBB6 is still in beta.