It's really nice to see some new surfacing tools, either x-nurbs plugin or implementing ACIS kernel into network and n-sided commands to add more features to them.
While it is not completely related to the x-nurbs discussion, I was thinking, Is it possible to make a plugin to connect moi to freecad library to use its surface filling tool inside moi?

I know it's not as powerful as x-nurbs, But, It has these features:
Making a surface with boundary curves/edges
Accepting guide curves/points
G1/G2 continuity

https://wiki.freecad.org/Surface_Filling