There isn't a good way to do that yet. We've been playing with some ideas, but offline sync like this is a surprisingly challenging problem -- it's easy to make something that works, but dramatically harder to make something that works at scale.
I can imagine that. I have seen some sync implementations for Backbone.js for instance a while back, but nothing that really worked well. Again, I am very surprised of how well PouchDB performs in this. Additionally, you get all (most) the features of CouchDB in the browser, you can even use the design documents that you create on the server.
