Jesus, I thought we had sorted out this debate a while back! Why stiffle creation by saying you can only use crap woods?

Make them entirely out of wood, any wood, if you find some scrap oak then good for you, if you can't then layer up the ply or MDF. It weighs bugger all and you could easily have 2 inch armour all around your electronics.

Weapon wise, everything should have come from wood working tools originally. Modify them to suit, use a chisel as the basis for an axe, use chainsaw chains and saw blades.

With these two rules here and the others of the featherweight category it gives the biggest amount of inovation you could have with this class. Stiffle it too much and most won't bother.