This is really more of a question that belongs in the Instrument Control board. You posted it in the data acquisition Idea Exchange which is for new ideas about data acquisition hardware. And a question about VISA is not the same as a question about DAQ. I imagine the next version of NI-VISA will come out with the next version of LabVIEW right around NI Week in August.
We are very aware of the upcoming Mac OS X Lion release. You can find more information about our expected support for this KnowledgeBase. You can still use the drivers as is if you boot into 32-bit kernel mode.
Regards,
Jon S. National Instruments LabVIEW NXG Product Owner