Hijacking this a little to say that we're working on a similar no-backend product called Hoist that does most of what Hoodie is but is a hosted, platform solution.
We do all the 'server' work so you can just build your app. Our platform provides API's for everything from Data management (just post and get JSON) and user management.
We're also working on integrating other cloud company API's so you can quickly get hooked up to them (and do the auth with tokens) on the server side and then use their API's in a fully client-side app.
Check it out: http://hoistapps.com
Would love to hear what anyone thinks if you give it a go. I can be emailed on ow@hoistapps.com
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