Not really, you'd just need a script to query the shouts by a userid, then update the shout field with the number of rows per userid.
Run the script once to "populate" it, and then from there on, your code will keep it going
*EDIT*
I think I found a way, found this post over on photopost
http://www.photopost.com/forum/showp...8&postcount=46
With a script to do similiar for counting the number of photos a person has uploaded.