On the other hand the stock is so light you are not going to have issues with torque so you could opt for a larger diameter cutter (for all convex work) which would keep the scallop height pretty low so if nothing else you could go with a 3 axis machine with a decent CAD/CAM package. You might still have to make it out of a number of blocks to optimize step over with different gradients but it might be 4 or 5 instead of the 3D jigsaw.
Best of luck with it
Noel.