I think this might work, wouldn't be too expensive if you had access to the equipment, and would make handle design very easy.
Step 1: create a detailed CAD drawing of your mold.
Step 2: fabricate the mold on a 3D design printer (prints objects in light plastic)
Step 3: coat the mold with plaster or something else which will air harden and keep fine details intact.
Step 4: use your new plastic mold (2 halves) with polymer clay and mold it around your pick or metal stock.
Step 5: profit!
-steve