The constraint on Surface is more likely to be the number of people you can physically fit around the table vs. the technology itself.

In constrast, I’m guessing from the video this wall uses infrared lasers in the bezel of the screen to create an invisible grid coordinate system. In this kind of screen, the screen itself can be much larger a Surface table, and therefore allow more people to simultaneously walk up the screen. But the screen might not recognize touches correctly if there is another person at the same place on the x-axis or same place on the y-axis that is also touching the wall, no?

For example, if you are breaking the plane of the infrared grid at coordinates (3,4), and I then try to break the plane at coordinates (3,6) will the screen properly detect my touch at X=3?

All that said, this looks like a fun project. How long did it take to build?