My company, Radius Networks, does sell different hardware configurations as well as software to broadcast as a beacon.

http://www.radiusnetworks.com/

I really love the USB powered model, especially for something like PunchClock. No batteries means no dead batteries.

http://store.radiusnetworks.com/products/radbeacon-usb

We also released a number of open source projects that can help with projects like this. Including the ibeacon cli (if you are on a mac just `brew install ibeacon`), or if you want more than iOS check out the Android iBeacon Library (https://github.com/RadiusNetworks/android-ibeacon-service).

Sorry for the shameless plug!