EdgeSweep (free Plugin)
EdgeSweep is a Generator Plugin, that generates SweepNurbs out of Edge-Selection Tags.
Deformations, Animation and Subdivisions (HyperNURBS) of the source object are considered, so that the sweeped spline should always match the selected edges. Spline interpolation and offset from the surface can be adjusted via the interface, as well as various options to adjust the sweep shape.