I'd really like for it to be hosted on something like workadventure (which is like gather.town or Topia). A custom virtual space for both large announcements/talks and little discussions.
I don't want to be a downer, organizing events is really hard. I think it is worth saying though, the best part of conferences are meeting people. If anything I feel like solarpunk would emphasize member-to-member connections more than other conferences. It being a zoom call it feels a bit, idk, like watching a low quality YouTube video that can't be paused.