Implementing Scrum without a well-defined Product Owner?

Hey all,

Working at a company that relies a lot on their engineers to figure out functionality and high level stuff and doesn't give much direction. We were looking for a more formal system for organization and project management and I suggested scrum. I'm kind of spear-heading this endeavor and doing a lot of reading and research but I'm finding we lack one of the key roles in scrum/agile: the product owner.

How do you guys recommend we generate user stories and other high level requirements without having someone to sit down and work with us? We do get little tidbits of information about requirements but again, nobody is sitting down and writing user stories so I figure we will have to do it.

Does anybody have experience with implementing Scrum in this kind of environment and have any advice? Trying to make the most out of this situation and be productive.

Also, if you have a recommendation for a better system that is even more self driven than Scrum and doesn't require a product owner, please let me know.

Thanks.