While digging through Usenet, I stumbled on these three unidentified tracks that pick apart three of the Beatles' original multitrack masters, isolating and highlighting pieces from "She's Leaving Home," "A Day in the Life," and "Come Together." It's an astounding, and very listenable, glimpse into their recording process.
Update: Removed the downloads, see update below.
Multitrack Analysis of She's Leaving Home Multitrack Analysis of A Day In the Life Multitrack Analysis of Come Together
Unfortunately, I don't have any information about the source. In the "Come Together" one, they mention one of the narrators is named "Steve." Beyond that, I haven't had any luck finding where they came from. Can anyone identify them? I'd love, love, love to hear more.
Update: It's from a BBC Radio 6 program called The Record Producers, hosted by Richard Allinson and Steve Levine, that aired last month. Unfortunately, the original BBC broadcast is no longer available on their site.
January 16, 2012: I was politely contacted by Steve Levine, creator of The Record Producers, who politely asked me to remove the sound clips. The BBC was granted permission to broadcast the sensitive Beatles master recordings with strict limitations: they could license it for only seven days after broadcast, and with the condition that they actively prevent non-authorized sources from making them available.
Unfortunately, there doesn't seem to be any legal way to purchase or listen to these recordings, and likely won't for some time.