I just found out that at least two other Open Source projects have been meaningful use certified.
OpenEMR has been partially certified.
Medspheres OpenVistA CareVue has been certified.
I hope to get more information about exactly what the partial certification means and what the meaningful use strategies of these organizations mean, but this means that the ClearHealth is no longer alone in certification. (Although from what I can tell, ClearHealth remains the only fully certified Open Source EHR)
I will write more when I know more…