mirror combined with 7 day incremental backup

[Darcy Bangsund]

Hello,

I'm trying to figure out how to keep a mirror and 7 day incremental 
backup between to 2 mount points.

I want to rsync everything from /mnt/production/ to 
/mnt/backup/production/ on the same server.
Nothing fancy.

But ,

I Want to utilize the --delete option for files that no longer exist on 
/mnt/production/ that  have been on /mnt/backup/production/ for longer 
then 7 days.

I can't use the BACKUPDIR=`date +%A`,  multiple directory method, as the 
amount of data I'm dealing with is to great to kept track of easily that way

I need the backup files to be a mirror of the original with 7 days of 
extra data.

If anyone could help I'd really appreciate it.

Thanx

darcy