That would be awesome. I had a graph file with around 6000 nodes (and many
more edges) and the only way I have managed to put it online was by
rendering a huge PNG which is sliced in to multiple bitmap images for
Seadragon. (example here: http://peterkrantz.com/v11n/rfc/). But that
method will always have problems with interactivity.
Multiple canvases would be very interesting to explore.