Estimotes are nice for production, but we built testing beacons out of Raspberry Pi's

http://developer.radiusnetworks.com/2013/10/09/how-to-make-a...

Here's a link the source for an app that we wrote for a Party that we threw recently..

https://github.com/backofthecup/HolidayParty

We built a few D3 visualizations of where users were at the party, and how fast they found hidden iBeacons... kind of like a treasure hunt game to demo the technology.