Also interested in this feature, being able to import 360 (cubemap files, assembled or not, or equirectangular or eventually less standard projection) or camera rigs. Please add my vote to the feature request in your DB.
Would help a lot aligning matterport-like data, where usually horizontal cubemaps align great, but ground faces do not because there is a strong difference in resolution and angle. XMP is not really an option in such cases, would be more tedious to re-align post first alignment.