I've been looking for it everywhere also, I finally found it today. Maybe you have already found it, but I thought I would help you out on this.
Bach's "Suite No. 1, S. 1007 in G Major" from his "Bach: Six Unaccompanied Cello Suites" cd.
There are about 4 pieces to this, he also performs the prelude with Yo-Yo Ma.
I hope it helps!