I think you are right that the role of Project Manager for a 1:1 implementation often falls to the Tech Director. Hopefully, you have found our Model Project Plan useful, and you can build an implementation team around you that can be responsible for specific areas within your project plan. Having your Curriculum Director, for example, be responsible for professional learning, is a logical delegation of responsibility. This approach still requires someone to facilitate timelines, and manage how the members of the committee communicate and document their progress.
The challenge we have found in some districts is that the person who has been charged with the role of Project Manager is not necessarily a person with any authority in the district. If the Project Manager does not have authority, it can make it very difficult for that person to hold others accountable to meet their responsibilities and timelines. If you contract with someone outside the district, as in Janna's comment, it can work well if their role is to guide the implementation team, but it still requires a central office figure on your implementation team to hold staff accountable for their project plan tasks, and "making it happen."
Good luck!