Ok, I put together a voltage regulator box to output 5v. Made some cables to run it with my Walmart battery and then out to my JB3. Worked great, ran the JB3 without a glitch with no batteries inside. Then I made a mini-usb cable and ran it with my Zen Micro. Like the MT, the Zen micro needs to have it's internal li-ion battery to run and it powers itself from the mini-usb port. My Zen Micro worked perfectly when being powered from the Walmart+voltage regulator box and the Micro showed that is was plugged in and charging normally.
I'm getting my MT delivered tomorrow, but from these tests, I'm pretty confident the MT will work fine with the Walmart battery + voltage regulator box.
Some pictures of the set-up: