Hi, CC.
Keep your eyes on the TV on the 15th of next month, a bunch of kids I teach will be performing at Crocfest up here, and one of the items will be a fingerstyle version of Summertime, a version of which has been posted here, somewhere.
We will use an Am raised to the third fret in place of the E7, with an added A note on the !st string 5th fret, also a Fm6 and a D+.
Info for our non-Aussie friends on Crocfest
http://www.crocfestivals.org.au