SimpleCrew (http://www.SimpleCrew.com - a mobile photo app for businesses, real estate investors, marketing street teams, etc...) is earning $1,600/mo RR right now... ~35 customers averaging just under $50/mo per customer.

The number isn't enough to support us in the US yet, but it excites us regardless because of its implications. Between the revenue and usage (weekly photo totals are consistently up and to the right) we believe we're on a reliable path to financial sustainability with this one:

Assuming ARPU stays at $50, we're earning 6 figures per founder (ignoring costs, just revenue) at just 333 customers, and we'll reach 7-figure earnings at 1,666 customers.

Those numbers are completely doable! God bless the economics of monthly recurring revenue, and DHH for spelling it out so clearly in his Startup School '08 presi (on YouTube). I can say without irony that that video has deeply influenced the course of my life.