Ok. I think I solved this problem . . . at least for me. After hard resetting and having the SMS unread count error show back up after receiving the next threaded message, I stumbled across this:
http://freewareppc.com/communication...eadcount.shtml
It contains an executable that has to be run from the device. Take a moment and read through the comments, download, transfer, run the executable, and restart. I didn't have to disable TF and/or start my messaging system from my Today Screen. The read count was fixed after I restarted and it seems to be working.
The only bi-product I noticed is running the executable seemed to have re-enabled my Verizon message sent notification. I just re-ran the Disable Verizon SMS Message Sent.cab and problem solved . . . at least for now.
I'll keep you posted.
The Disable Verizon SMS Message Sent.cab I used could be found here:
http://forum.xda-developers.com/showthread.php?t=561443