Stackless is the opposite of what he wants, which is to take advantage of multi-core or multi-processor resources.
The quote above does mention that "[Stackless] does not however allow you to take advantage of multi-core or multi-processor resources. It simply allows you to squeeze the most amount of work out of a single threaded process...".
Depending on the application and its particular implementation, actually Stackless could be the right solution. Which is why I brought it up. In fact, it now looks as though he might go with Stackless, just like EVE online did :)
"Stackless python does not make use of any kind of multi-core environment it runs on."
http://stackoverflow.com/questions/377254/stackless-python-a...