I'm not sure how to go about this but I am trying to make a column to store modified time and user. Something like:
ID Title Multiple Reviewers 321 Dog House John Appleseed on Dec 31 2012 Steve Ballmer on Jan 12 2012 John Appleseed on Jan 31 2012
I think you have two options here.
You can turn on Version History for this list. I won't show it like you have above, but it will collect the data.
You can create a new multiple lines column and append the new modified information to that column.