I have an update on the signal strength.
The antenna is confirmed to be located on the battery cover. Maybe this is old news that everyone already knows, but I'm just throwing it out there. Take off the battery cover while the phone is on, and signal drops immediately.
So with that said, I swapped back from the extended battery to the stock battery and cover, and the signal strength is the same as the extended cover. I'm thinking now at this point I have a defective unit, or it's just the way this phone is by design. My coworker is going to pick up a Rezound sometime soon, within a day or two, and we will do a side-by-side comparison of signal strength using an app that measures db gain and loss real time, and graphs it out.
I'll keep you posted.