I don't think it will happen either. AA was buying TWA in an attempt for the assetts but also to save the airline. UA was buying US for assetts and nothing else. I really don't think CO and DL will go through, the reasons are assetts and nothing else. I think the only major merger that will/would have gone/go through was AA/TWA. I don't think UA/US, CO/DL will happen.
Give me a break, I created this username when I was a kid...