Here's what appeared to fix it. Quite by mistake, I forgot to reinsert the battery after a "test" of some sort (I had only tried a zillion things over the past hours). I then plugged the USB cable into the phone (cable connected to my computer, of course), and it went right to the old "Emergency Mode" screen. I got busy (doing REAL work...lol...) and after 5-10 minutes noticed that the phone display had changed -- it now had a big battery graphic with bold print "BATTERY REQUIRED" at the bottom. I thought "what??", but then looked and saw the battery on my desk. So I unhooked the cable (which obviously powered off the phone -- no power source now), inserted the battery, put the cover back on, and then just pressed the Power button -AND- reconnected the cable (the order of those 2 things I'm not sure about -- I *think* I pressed power first, but can't swear to it). THE PHONE WENT TO IHO RECOVERY!!!!! WooHoo! I knew I could surely get it from this point.
So I then put the Xionia recovery (Xionia_CWMA_12518.6_VM_Recovery-signed.zip -- just google for that filename and find a working download site) in the root folder of my microSD card, inserted the card, and did "install zip from sdcard" (and selected that file). I had originally tried ".4" version for VM phones, but it would not install ("Installation aborted"). This file installed perfectly, and after rebooting I now had new Xionia recovery. I went under Advanced on the menu, and executed the "Fix Recovery Bootloop" option (I think that was the name). It ran, I rebooted, and VOILA -- MY PHONE IS ALIVE!!
Hope that helps someone else who runs into the same thing. It really appears that connecting via USB with NO BATTERY INSTALLED was the key to getting out of Emergency Mode.
Cheers!
Kevin