What I still haven't figured out is the best way to do responsive web apps with Backbone.js. Off the top of my head I can only think of two, Flow and AudioVroom. Flow uses separate javascripts for both versions. AudioVroom, has one file, but it's minified and I haven't had a chance to trying to reverse engineer it to see how they implemented the different layouts in a mobile, tablet and desktop environment.
We're approaching that same subject now for our development this week. That will probably lead to another blog post ;-) But we are having some luck with Django Compressor and doing CDN hosting. RE:Different layouts...One thing we've tried to do is rely on CSS as much as possible to do the heavy lifting . As for re-using accross mobile and web, you might want to look into putting all of your low level collection and model code into a git submodule or the equivalent so that it can be re-used accross projects.
