Hmm, missed the refresh of this last time.

Some brilliant players who've taken electric techniques or songs and put them on the acoustic guitar are Michael Hedges, Eric Roche (both sadly deceased), Thomas Leeb and Rodrigo y Gabriela. Rodrigo y Gabriela in particular play some amazing flamenco-style covers of Metallica songs. If he's into the whole crossover thing, I suspect he'll like them.

Graham.