In reply to beardy mike:
Target weight <=600g
Full strength clip-in/spike pommel
Second high grip with same pick-to-handle angle as the main grip
Adjustable handle angle (see Cassin X-Dream)
One piece shaft and head ala Grivel Machine 3.0
Textured Plastidipped shaft and head for grip, damping and insulation
Have a look at the krukonogi picks if you haven't already, or it make it compatible with Grivel's picks
A curved extendable shaft that is strong, durable and light would be quite an engineering coup
Personal preference is for tools with a balance point 2/3 to 3/4 towards the head