I know it's based heavily on GDocs, but my workflow is based around Dropbox. Maybe something could be rigged up there.
As an aside, I was sad to see Bespin go. It used canvas for rendering, while Ace uses the DOM. While the Ace team had good reasons for this, Bespin just looked so.. pretty..
I didn't realize Bespin was gone, that's a shame, but it looks like they're making a lot of progress. Being in the process of moving from a (dying) desktop to a laptop, I appreciate things like Chrome syncing where I don't have to spend a whole day configuring my browser any more. I am okay with moving more of my apps to the web, assuming offline mode is always an option. I look forward to more "cloud" products like this.