Thanks for the update loscuber. I still haven't had time to dig into this yet (I think I'm secretly still hoping it fixes itself automagically after drying for a few months!). Good to have something else to look to though. Thus far it seems the most common culprit is the BCM based on my forum searching. The cube for me is my fun car so I've been driving my gas guzzling truck while waiting for winter to leave so I can rip into the cube without freezing.
As of now the cube will run and drive however it's very gutless (high revs, slowwww acceleration). That's the only running symptom. Turning off I still have to disconnect the neg battery terminal and then hit the button.