There were many occasions in which either Brian or Roger provided vocals for one-time performances which would never be repeated. To name just two of them for each member, we can mention "Thay Will Be The Day" and the recent "Hound Dog" for Brian, or "Revolution" or "Cosmos Rockin'" for Roger.
This particular performance, which took place at the Cowdray Park on 21st June 2002, seems to have been completely forgotten, and ignored by the bootlegging community, collectors or even casual fans, despite the fact that many "bootlegable" artists took part of it (Gilmour, Geldof, Ringo, Rutherford and our Roger, to name a few).
Some info and pics can be found here: http://www.pinkfloydz.com/Cowdray/cowdray_park_21_june_2002.htm
And three videos can be found here, which unfortunately none of them feature Roger footage, despite two pics at the end of one of them: http://www.youtube.com/watch?v=X5kAonMuFLA http://www.youtube.com/watch?v=63uFi0syCwA http://www.youtube.com/watch?v=uMIB3dsn1r8
This charity gig took place a few months after the passing of George Harrison, and it's quite strange and hard to believe that it has been buried in the records of the music fans.
For us, Queen fans, this concert gave birth not to one, but to three unique performances by Roger, that would never take place again, plus one that would be repeated only once again for good, a bit less than a year later. Yet, all of them still remain unavailable to the ears and joy of us all: I am taking of something no less interesting that Roger providing vocals for the Beatles tunes "I Feel Fine", "I Am The Warlus", Lennon's classic "Jealous Guy" (which he would cover just once again for the never aired SAS Band show from 2003), and George Harrison's "My Sweet Lord", but this time as part of the "All Star Finale" (ala "Do They Know It's Christmas").
I write this article just to make at least a bit of justice for this very interesting concert, which united on stage a Beatle and a Queen member for one of the very few occasions in that this happened (being others Live Aid, Jubilee and Band Du Lac 2005).
I hope that one day we can get access to a recording of it, specially to Roger's set.