As much as I'd love to work on something like a Conquests game, I think it would be a case of handing a company a (brilliant) design document and saying, please build this. I think Steve and I love designing too much to work with a big name like her. That said, I'd play the hell out of the game when it came out!
EDIT: To clarify, I say that with no knowledge of how Christy Marx (or another designer I admire like Scott Murphy or Jane Jensen) works, whether it would be collaboratively or what. But I'd be always second guessing my own opinions and thoughts because I hold these people in such high regard and I'd want to do whatever they thought.