I’m not personally familiar with a knowledge cafe, so I’m really just going from what Wikipedia says about them.
That said, it sounds like it would be a fun experiment for a THATCamp. The thing that seems to distinguish it from most THATCamp sessions is the part where the group breaks into smaller groups to discuss the same topic. Tak, what I imagine is a knowledge cafe that spans over two „regularny” THATCamp sessions, one with the big group all together, and one where people are broken into the groups.
Assuming there’s a big room where people all meet to build the schedule, that room might work great as the place to span over the session. People would meet together to start the session, then part way through break into groups in the same room.
Is that making sense from your experience of knowledge cafes?