Here is a good example from swimming using a velocity meter, with synchronized video.

http://www.teamtermin.com/velocity_meter_video.shtml

More Ideas?

There will be difficulties though :
- Access to hardware. To develop and test the sensor acquisition, the developer would need to have the hardware that is sending the data plugged in.
- Protocols and formats. For devices that send digital data they sometimes transmit using their own proprietary format understood only by their application…

I guess that would be a good candidate for a plug-in architecture where people with access to the specific hardware could help build a plugin for it, and then get it integrated in the main codeline.

First of all, it would be nice to have an idea of the type of devices/data we are talking about .
Can you point to some examples sensors ?

- I had started to look into strength platforms used by podiatrics a long time ago (surface sensors), but access to hardware is definitely an issue for real time capture of data.
- There are also other strength platforms for more general use. (anyone with a link to a specific vendor or hardware?) 
- Pulse recording equipement. (not sure of the actual usefulness to have this data along the video ?)
- others ?

Please point to examples of "accelerometry" sensors and other type of sensors you may have in mind!