I think I found the best (yet not simple) fix so far, that lets you not lose your text messages (but you will lose other application data that isn't synced some other way - though the same instructions could be applied to those apps, but is too complicated for me right now). First, backup your phone (and sync any photos to iPhoto, contacts, etc - things not included in iPhone backups), and make like 100 extra copies of that backup so you don't screw it up. The backup is found here:
~/Library/Application Support/MobileSync/Backup
If you have other backups and are confused by the weird folder names, just move all the backups somewhere else, right click your phone in iTunes and backup. That'll leave just one backup folder. Let's call this OLD backup.
After you are 1000000% sure you have that folder backed up, go into iTunes and restore your phone as a new phone. Once you've done that, make sure there the backup folder is empty again, and backup your phone. Let's call this NEW backup. Make a copy of it on your desktop.
What you'll want to do to get your text messages back is the following. In the OLD backup, find the file called "3d0d7e5fb2ce288813306e4d4636395e047a3d28" and copy it into the original (NOT on your desktop) NEW backup folder. Do the same thing with info.plist, Manifest.bmdb, Manifest.mbdx, Manifest.plist and Status.plist.
Now go into iTunes and restore from backup. There should only be one backup there, which is our modified backup. It'll do some work, then freak out and give an error. However, once it finishes, your text messages should be back. Don't ask me why, but for some reason now the MMS and cell data stopped working again for me, so we aren't done.
Delete all the iPhone backups in the backup folder again. Copy the NEW backup from the desktop into the iPhone backup folder. Copy from the OLD backup the file "3d0d7e5fb2ce288813306e4d4636395e047a3d28" into the NEW backup that is now in the backups location.
Restore the phone again using what should still be the only backup. It will give an error again, but when it finishes, you should have MMS and data again. Visual voicemail took a minute to start working.
If you are not confused by the end of what I just wrote, then god bless you. Good luck!
