Invincible will end with issue 144. Considering the recent release schedule that could take QUITE a while.
There's a number of sources out there, just linked to a non-comic message board one
In one I read Kirkman feared reading an Invincible comic one day he thought was awful by some kid he didn't know. Guess that means he won't be just letting anyone at Image use his character. Wonder what stories Marvel and DC character creators would like to have removed from history. Creator owned is a good thing.
That's too bad. I do enjoy the series after you pointed me in its direction. Sounds like he's too busy with the other two books as well as all his tv projects. Sales certainly were not impressive, either, so it appears something had to give. I often wonder how some if these independent titles can continue when looking at sales. Its too bad the indies aren't more popular as they are usually of much higher quality than what we get from Marvel or DC.