Just do it your self, https://gist.github.com/mariocesar/3f3e63cd422e1024d7e5 (If anyone has enhancements please fork or comment)

Time before when Canonical announce Ubuntu One was going to be discontinued I comment how I depend on U1 to deploy my static websites, like 30 static websites some of them with simple .php scripts that manage contact forms or feed aggregation, it's pretty easy to do and still don't get why so much people put so much effort on making it a SaaS, we are talking about a little sysadmin work.

I have no option that use Dropbox as a backend as most of my clients use it, but it's pretty obvious you can setup the same features with other services.