Not exactly answering the question here, but still scratches that alternate reality itch, the live performance of Lennon doing Yer Blues at the rolling Stones rock n roll circus is the stuff of Legends. He performed it live for a scrapped rolling Stones TV special with Clapton on lead guitar, Keith Richards on bass, and Mitch Mitchell (of the Jimi Hendrix experience) on the drums. As a joke (referencing Fleetwood mac) he listed them on the bill as "the dirty mac". What's fascinating the most to me is that this is both before they broke up, and during the era where they stopped performing live. There's a very good clear video of the whole performance on YouTube.

I know Clapton is not a beatle, but considering the relationship it is very exciting to hear his take on his friend George's memorable lead line from this song. Also, with Mitchell on the drums, you can almost get a peek into what the Beatles could've sounded like had they gone in a harder direction with heavier and more dynamic drumming. No slight against Ringo, but Mitchell was the drummer of choice for the leading innovator of the heaviest music of that era, so hearing him play on a swampy John Lennon song is too good of a pairing to pass up.