Bash rsync but move not delete

There might be an easy solution to my problem, or maybe not, but here it is.

I am trying to rsync a Volume with 1.5 terabytes of data and send it via fibre channel to a raid array. Now normally when I rsync it scans through everything and, before copying anything, deletes any files that have been changed and will be copied over. Rather then doing this delete i would like it to move those files that have been changed to another location on the same drive. here is the script that i have:

rsync -avzr --exclude="*.DS_Store" --exclude="eBooks/" --exclude="archive/" --exclude="prints/" --delete /Volumes/image/$WORK /Volumes/XRAID/$WORK

I'd appreciate any help or suggestions.

Thanks

short suggestion: Maybe hard links can help you. Let a script create a directory hierachy identical to your data and populate it with hard links to the actual data. After an rsync run over one of those directories in the other the old data persist. (Can nicely be extended to use dirs representing one day each and giving you the ability to walk through exact old dirs without having to have all data on disk more than one time.)