ProfesseurThibault have received some telemetry data from their app and found it running on Microsoftâ€™s Windows Phone 8 virtual machine.
The numbers indicate that Windows Phone 8 is still under development, with the build number incrementing over the course of days.
The latest build number now on record is 8.0.9730.0, recorded on the 4/7/2012. Windows 8 is expected to Release to Manufacturers this month, and with Windows Phone 8 likely on the same time scale we should see these build numbers stabilize soon, indicating a final build has been shipped to OEMs for integration.
Interestingly we have not seen any significant post-Tango builds yet, indicating that the 7.8 update may be on another development trajectory.
Update: Gudipati in the comments has a more recent build number, 8.0.9735, from the 6/7/2012, again indicating the build number is still increasing rapidly.