Using a point would probably be the best solution.
To achieve the glow though, you’ll have to write a custom shader for the PointPrimitiveCollection
You can see the shaders we currently use here:
The shaders are added to the primitive in PointPrimitiveCollection.update:
And here is an example of how to add a point using a point primitive collection:
var pointPrimitives = scene.primitives.add(new Cesium.PointPrimitiveCollection());
color : Cesium.Color.YELLOW,
position : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883)
If you do decide to implement this, let us know! We would love the contribution back. I think this is something that would be helpful to a bunch of other people.
You can check out our build guide for instructions for getting and building the code: https://github.com/AnalyticalGraphicsInc/cesium/tree/master/Documentation/Contributors/BuildGuide
It’s a bit more work to connect this to the Entity API. Let me know if you get it working at the primitive level and I can give you the steps you need to hook it up at the entity level.