Scott,
I would also love to know when we can start loading vector tile packages to Collector (for starter) as we can do with tile packages.
Talking to support at Esri UK yesterday I was told that this is not in the pipeline apparently, although would love to hear Esri Inc's comment on the subject. We have quite a lot of projects where we could make use of the vtpk files instead of uploading background OS MasterMap Topography/ITN/etc. layers to AGOL first and then download to the devices. Very time consuming and counter-productive...
Zoltan