Yes.. I suppose one material that leaps to mind is CF. I have never made my own structures with it but I should imagine that making a square cross-section tube would be fairly easy. One could laminate a titanium/(other light metal) in the engine mount area pretty easily.

But from what I gather you have other designs that build even faster? Where do I go to get these? Spadworld? Do you have a particular type of design in mind that is derivative of the Gremlin (for when my PVC inevitably cracks )?

cheers, /S.