I am trying to figure out if there are plans for a third, pure C/C++ or java SDK for the Playbook.
Anyone know?
Yes there are plans for both. However both are scheduled for later on after the official launch with an ETA of Summer 2011 (details came from the 2011 Developer Day in Toronto yesterday.)
This also includes the tools to port Android Apps to run in the "Android App Viewer".
Update: The schedule has changed a bit but there is now more information available about the upcoming "BB 10" platform expected around February/March of 2012. (Note it was originally called "BBX")
BB 10 Announced: http://crackberry.com/bbx-announced-devcon-2011-today
Developers interested in developing on the new platform can gain early access here: https://bdsc.webapps.blackberry.com/native/