I don't think so.. not in a Sketch pattern, because it's not editable at the sketch level for any user. If it was, then I could see how some API code could get in there and change it.
But I might be wrong... Any API Guru's out there want to try this one?
I've tried and failed to find anything that works.
This might be a little cumbersome, but if I have a 2D contour to pattern, I turn the contour into an extruded surface, pattern the surface, and use the patterned surface edge. The reason I do this is because the surface sketch can be edited to add and remove entities, but the dependent features still recognize the surface.
An example of this is in the torsion spring model on this site: