What would be good is if 2 cores could work in tandem within the cpu it's self to output 1 single thread at twice the speed. So if you had 8 cores running at 4ghz, it could change to 7 cores (1@8ghz and 6@4ghz) when it needs the extra single core power. This would be so good as you would not need the OS to use more than one core for one job it's self. I wonder if it is possible this could be done with a different cpu architecture in years to come.
Wasn't there some odd rumour with Bulldozer about being able to do this? Obviously it doesn't, but I remember Bulldozer having a lot of weird rumours of how it would be an Intel killer

Don't even think it's possible for two cores to work together acting as one. And it probably wouldn't scale where the new combined core is twice the clock speed, but more likely to be wider to offer higher IPC.