The Connect surface tool by Dimitri.

[Dimitri]

I am still trying to find a practical way for a solution to this need. It seems that approaching it by a 'plane cut' solution is difficult. What about locking all the vertices, leaving only the two to be connected, and connect them (in wireframe and view alignment mode) by the already existent 'connect' tool?

In such a case there would be the need to have a 'lock selected' command for the vertices of course.

Just an idea for discussion... : - )