I picked this one up as well as the Silver Collection years ago precisely because that’s about all of the Harry James MGM you’re going to find on CD—domestically speaking, anyway. (Not sure if more has been reissued in Japan or elsewhere.) I once asked either Michael or Scott at Mosaic about the possibility of a James MGM set. They agreed that it was an excellent band, but that such a set was unlikely. Not sure how well that James/Krupa Capitol set sold, but that might have been the rationale for their hesitancy re a James MGM collection.
Per the thread topic and speaking of Bill Finegan, don’t sleep on Tommy Dorsey’s late-1940s postwar big band. This Bluebird compilation, with notes by Loren Schoenberg, provides a good overview:
Tommy Dorsey: The Postwar Era
There are a couple of Hep CDs that document this period as well.