[rzendacott]

Zapier (YC S12) did something similar to determine demand for their initial product. I heard Bryan Helmig (co-founder) give a great talk on the subject, and it seemed to work very well for them:

https://zapier.com/blog/anatomy-of-sale-or-how-andrew-warner...

http://bryanhelmig.com/bootstrapping-an-idea-the-paid-beta/