Pass markers as canvas instead of urls?

[David Karger]

I'm generating lots of custom markers for my maps at runtime using canvas.  Given that gmaps is also using canvas, there's some annoying wasted computation involved in extracting my canvas as a data: url and passing it to gmaps as the url of a marker so that gmaps can parse the data url as an image and write it back into canvas.  Is there any way for me to just pass the canvas containing my marker directly to gmaps?