I believe Wesabe had an implementation that did this. From http://blog.precipice.org/why-wesabe-lost-to-mint/ http://blog.precipice.org/why-wesabe-lost-to-mint

I believe Wesabe had an implementation that did this. From http://blog.precipice.org/why-wesabe-lost-to-mint/ http://blog.precipice.org/why-wesabe-lost-to-mint/ Wesabe built our own data acquisition system, first using downloadable client programs (partially because that was easier and partially to preserve users’ privacy)