Hello Geoff, the problem of using graphene as a material for uber-strong composits is -- at least for the moment -- the ubercost and low feasibility of creating long fibers in bulk/industrial quantities.... Typically, structural composites are formed by long strands of carbon fiber woven into cloth, soaked into uncured epoxy, transported and manipulated at about -50C, then shaped and layered, and finally cured to solidity inside autoclaves. One of the keys is "long fibers"... And that is one of the problems with current bulk manufacturing of graphene.... It's easy/cheap to create solutions containing self-standing micro-sheets.... But self-standing long fibers are a different matter all together. Th other problem of graphene is that while it has very desirable tensil strength, it has poor bending/torsion characteristics.... This might preclude its usage in many wiring applications, in spite it having electric resistivity less than Silver.
Perhaps at some point it might be feasible to coat conducting lines on boards and circuit components with a monoatomic layers of graphene... But there is no guarantee that the audible result would be desirable.
Rather, if the construction of graphene-based composites were feasible, it would be interesting to try them for components where rigidity and low mass can have a positive impact... E.g. speaker diaphragms, tone arms, etc...
G.
