We have now released a second beta! One big change to note in this release is that the OpenStreetMap, Carto and USGS basemaps are now being displayed by the Mapbox mapping engine. You can read more about this change here. If you use those basemaps, please be sure to test and give us any feedback you may have.
I haven't tried this yet but I think it's possible if you add repeat instances for existing values. Those would only have calculates in them so would not be user-visible. I think you'd have to use a dynamically defined repeat count to make it work. I don't think it will be usable with much more than a couple hundred existing Entities! You can add calculates with property names for styling in those repeat instances.