Update: Erik reports that it sometimes does not work even if all triangles have been adjusted so no angle is smaller than 1 degree. Also, in some cases, it does work, even with angles that are smaller still, below 0.11 degrees. So, I reopened the development issue REVIT-130028 [TessellatedShapeBuilder solid creation throws Could not create consistent vertex list -- 14029415] and await further advice from the development team.
Cheers,
Jeremy