If I upload a file that already exists up on google docs (because I didn't realize I already uploaded it, or because I'm doing a bulk upload), I get a second copy of the file. Is there any way to get google docs to check for duplicates?
There is no such option in Google Docs as such . But there may be possibility of using GreeseMonkey Scripts or third-party browser extensions for doing so.
But there the problem would be that we have to match the file-name and size of each newly uploaded file with all the existing once, but Google Docs does not shows the file sizes of individual files in anyway.
The third-party extension would have to download the all the files to make it possible - which is not practical and also not possible because Google Docs sometimes converts the uploaded files into it's own format - screws the formatting and file size also alters.
So, basically not possible.