I started building something like this right before state competitions last year, then abandoned it when the robot code called for help. You can see the incomplete version here:
http://flatmountainscout.appspot.com. Fyi the login system is not connected to anything, so you can do whatever you want with it.
It runs from a google app-engine server, which has a development server you can run locally. The eventual goal was to have some laptops networked together for scouters, with one server, but then be able to export all of the data to a flash drive. You would then run the flash drive back to another server setup in the pits and import the data there. It would also have the ability to export to the web version, and import from tba, if internet were available.