Thanks for the information Brent! I don’t think it’s likely that we’re going to be able to add native shapefile support to Cesium in the near future, but if anyone would like to contribute that feature we would be happy to accept a pull request!
Something we have talked about is adding shapefile processing support to our upcoming cesium.com service. The service would convert the shapefiles to a 3D tiles vector format, and that would make it easier for folks to add their shapefile data to a Cesium application.
That functionality won’t be in our initial cesium.com release, but it seems to be of increasing priority because a lot of people have shapefiles they would like to see in Cesium.
You can learn more about our plans for cesium.com here: https://www.cesium.com/