cleanram can do this.
Here is my personal set up that works VERY well:
spb backup to backup and reset every morning at 5am monday (keep only 5 backups), and cleanram to reset tue-sun. I never have SOD's or problems during the day, and have been doing this for months.
it's an awesome way to keep your phone reliable.
http://forum.ppcgeeks.com/attachment...d-cleanram.cab