This may have already been covered on this board... but RCA has an authorized fan division of their label for Elvis rarity releases called Follow That Dream. They present rare recording sessions and expanded albums (the new Elvis at Stax sessions (1973), which resulted in 3 albums... Raised on Rock, Good Times and Promised Land... has, I believe, 4 or 5 discs of material, alternate takers, rehearsals, etc. The legendary FTD Jungle Room Sessions collection contains the sessions for Elvis' last two studio albums, in February and October 1976, including an unreleased rocker that Elvis never managed to find time to cut a lead vocal for). They also feature earlier sessions, recently documenting the Elvis Is Back 1960 Nashville project.
Additionally, they've released a ton of rare live shows from 1969-1977... all board recordings (with one exception - a legendary 12/31/76 live show that is an excellent audience recording of probably his best late period show).
These live shows contain complete concerts, plus bonus tracks or rare songs performed at other venues during tours. As an example, a show from Fall of 1974 (10/31), contains bonus tracks from other venues during that same two week tour.
In the last few weeks, I've listened to 6 board recordings of live shows from 1976 alone... documenting that entire year. And that's just scratching the surface. They're usually limited editions, available via the Elvis official website. A single disc costs around $25. A double (I just listed two double CD discs of shows from Chicago(2), Birmingham and Dallas from October and December of 1976) costs around $29. Great packaging and faultless audio quality.
It seems to me that the Beach Boys / BRI org could be doing the same thing with vault material. FTD has been doing this successfully with the Elvis vault for 14 years!
Here's the website:
http://www.elvis.com/ftdreleases/