Curiosity: You, sir, are a genious.
It was the fact that everything was plugged in through the hub. I plugged the touchscreen into the other port on the Mobo, and voilla! problem solved.
The 6 volt adapter's still providing power, but clearly it's not the 4 amps it would like to have. Plugging in the 4 amp ac-dc one that was included, didn't make any difference.