Top of my head, and sorry if I'm too vague but I think I read somewhere (Avakian?, Bill Crow?) that some of the tapes from the concerts are much better than the "official" album itself. Releasing those might be another possibility.
This was also the famous tour where Phil Woods shouted "F*** you, King" in the balcony right above BG's, who heard him perfectly.
One other related album is "Jazz Mission to Moscow" (Colpix SCP 433) by men from the BG Orchestra (Jimmy Maxwell, Marky Markowitz, tp; Willie Dennis, tb; Phil Woods, cl,as; Jerry Dodgion, fl,as; Zoot Sims, ts; Gene Allen, bs; Bill Crow, b; Mel Lewis, d; Al Cohn, arr, cond), plus Eddie Costa on piano in his last official recording. This was planned by Jack Lewis (formerly with RCA) who was waiting for the men at the airport in order to release the record before RCA's.
Colpix seems to be currently owned by EMI...
F U