hm, yeah, all good advice.
Basically, I was just looking if I can duplicate a feature I saw at another webhost offering:
VaultPress makes it easy to keep an up-to-date backup of your site with both daily and realtime syncing of all your WordPress content.
I know that is quite a service they are offering so I was looking into something like that :-)
VaultPress will backup every post, comment, media file, revision and dash*board setting as they happen.
So I guess the closest I can do to that is, have a plugin that hooks into different Wordpress actions and runs a mysqldump or export on certain tables that have changed...
Thanks for all the feedback though :-)