Dont be put off using a plywood base to start with, we,re still using one. Its cheap, easy to work as you go through the prototyping stages, its as flexible and resilient as most other materials IMHO. As long as you fit some reasonable protection around the edges and a thin skin of something more trendy/expensive over the outside its fine againest most weopons weve encountered.

Once youve got the design finalised then you can use more expensive materials, initial testing is far, far cheaper in ply than polycarb.

Dont forget the main advantage of ply is that if/when it gets trashed it makes far better firelighting kindling than either polycarb or titanium

regards

Tim Jones