This is another approach/idea that I implemented some weeks ago in my FTP Client ... but to be honest I haven't worked much on the bugs/improvements
1- Install and run the PS3 FTP Client 2.9+
2- Set the download folder to your dropbox folder (public or private)
3- Connect to the PS3
4- Browse to /dev_hdd0/
5- Press Ctrl+Enter on the "home" folder to download/sync the folder with your PC
The program will backup your saves/rif/edats/etc. to your download folder.
(The first time it will take a while to download everything)
Then the next time, when you press Ctrl+Enter on "home" folder, it will download/update only the new files. So the download/sync should be faster
Then dropbox will sync everything automatically in the downloaded "home" folder with the cloud... making it available from anywhere in the world
I know it is not the best approach, but it should work too.
A better approach would be a FTP Server running on the PS3 that sync the files directly with DropBox or transfer the files to a PC or FTP.