Hi,
Since you do not need Flash and to be supported in all OS, so we recommend JAVA technology or Python to make this whiteboard feature for real-time tutoring experience for people.
I saw Brainfuse and Scribbler and could not find resemblence because Scribbler is meant for Card customization and Brainfuse sems to have based in old ASP. Since we know how whiteboard works so, we are really interested to work in this project.
Lets discuss.
Regards,
Mit-