I know that I can turn iOS devices into iBeacons (Can an iOS7 device act as an iBeacon?). Unfortunately, I only have one device and my beacons have not arrived yet. So I was
This is possible with OSX Mavericks, but not in Mountain Lion and earlier versions of the OS. My company, Radius Networks, has a MacBeacon app that does this on Mavericks.
In OSX Mountain Lion, unlike iOS 6+, there is no built-in support for the Bluetooth peripheral mode you need to advertise like an iBeacon. This means rolling your own low-level Bluetooth code, which is not easy to say the least.
But there is a solution for older operating systems. I paired an external Bluetooth dongle on my Mac with a VirtualBox VM running Linux and achieved what you are looking for. My company made this VM available for a free download here: http://developer.radiusnetworks.com/ibeacon/