My nominees are Full Moon Fair’s cover of Night Comes In on a Richard Thompson tribute record, and Dick Gaughan’s astonishing run at Floo’ers o’ the Forest from his record with Andy Irvine. Full Moon Fair appears to have been a one-time combo of David Lindley and Danny Carnahan.
Ron Kavana played a couple of blinders on the album Galway To Graceland. I’ll dig it out later and refresh my memory.
Wow. That’s pretty crazy. He gets some
interesting sounds out of that thing.
It’s not all electric guitar - I think Lindley is playing one of his trademark ethnic non-guitars, as well. Back then he was ahead of the crowd.
My suggestion would be “Magnus Memory” on Slàinte Mhat’s 2002 album “Va” - the Dobro-solo, played with just a weeeee bit of nice electric distortion, is simple, but extremely effective - giving the whole just the simply perfect arrangement! 
It would be a disgrace not to nominate a few Richard Thompson solos. But which ones? There are dozens of very good ones. Every time I listen to an album or watch a DVD of him some guitar playing blows me away but no single song stands out.