Ok, I figured out a way to make it work. Since CGI scripts are run as the user who created them, you can set one up to run the svn update for you. Here's what I did:
1) Created a script in a secured folder, in my dev site.
disable filename globbing
echo Content-type: text/plain
echo "---++New Commit/Update++---"
/usr/bin/svn update /home/.onion/icetek/dev.icetek-studios.com
then I setup my post-commit file like this:
wget -O - --http-user=RANDOM_STRING --http-passwd=RANDOM_STRING http://dev.icetek-studios.com/scripts/update-dev.cgi >> /home/______/status/post-commit-log.txt
This way, I get a log of every update made to the dev site. I will probably be using this for more then just this site, so I will probably make the cgi script more complex, and be able to update different sites, we'll see. This works for now.