Set day/time to backup database?

It would be nice if we could set what day we would like the database to backup. I run 10+ WordPress installations on my VPS and they all try and backup around the same time on Wed. It would be nice if I could stagger the databases to backup during weekend evenings when traffic is much slower.

http://ww.wp.xz.cn/plugins/all-in-one-wp-security-and-firewall/