This sounds like an interesting idea. Because the Google Docs API seems fairly easy to work with it should be possible to create a plugin for this purpose. I guess it would be very generic, however, just adding a new record for each scanned barcode to a table of your choice (with the possibility to add some text as well). lardman is also working on an itemdb plugin which I guess could be expanded to have some kind of CSV export functionality. I guess this would in the long term be a more neat solution to register large amounts of data. I'll have a look at a Google Docs plugin if I get the time (no promises, though).