well - after 10-12 hours of work over the last several days trying everything and several conversations with Sprint - they're going to send me a replacement phone free of charge. Of course it's not the phone, something happened in the upgrade process from 6.0 to 6.1 - I KNEW I NEVER SHOULD HAVE DONE IT!
So I guess the new device will be 6.1. What I perhaps incorrectly assumed is that you can upgrade then perform a full restore, but the restore files were of course made with the old WM6.0 OS - maybe that's the issue?
What a hassle - I finally got the phone the way I wanted it with many 3rd party programs functioning and I go and upgrade with a new OS that really doesn't add that much.
Here's a link so it's not just me. -
http://forum.xda-developers.com/showthread.php?t=371071
Oh well - live and learn!