Seatgeek just posted about moving their maps implementation to use canvas
http://chairnerd.seatgeek.com/high-performance-map-interactions-using-html5-canvas/
They also explain how they implemented performant hover/hit testing
http://chairnerd.seatgeek.com/spatial-data-structures-for-better-map-interactions/
I thought it might be useful for the bokeh team.

