Vladimir amazing work! Just this mean, we can style a raw vector map from mapbox without applying styles? I'm not able currently style maps with a huge number of point on vector mapbox due to the tile processing limit. I am able to host the vector file though. Being able to directly style raw vector files on the client really opens the doors to a realm of possibilities.
Yes, upcoming Mapbox Studio release will allow you to author vector tiles for GL (with custom data), which you can fully style on the client in turn. Note that Mapbox GL is a collaborative effort of a big talented team — a lot of people worked on this, I'm only a minor part.
What about support for mouseovers? Is that possible? Something we can expect soon?