I've gotten some great suggestions from emailers, commenters and friends about candidates for under-appreciated guitarists, and I will likely use many of the suggestions.
But for now, I have my own list to work through.
Jan Akkerman was the guitarist for the Dutch group Focus in the '70s. During the really exploratory days of progressive rock, Focus made some unique music. Including yodeling.
Here's his website: http://www.janakkerman.nl/
Here's a video of their biggest U.S. hit, Hocus Pocus:
But here's what made Akkerman really special. Not only was he a pretty state-of-the-art rock guitarist, but he some pretty serious jazz skills:
Truly a fine player.