Mosaic did have a Lunceford Decca set on the drawing board, several years ago... shortly before Universal slammed the door on them for awhile. From what I've heard, it's very unlikely that it will ever be done, even though Universal has since given Mosaic the keys to the vaults on occasion. Isn't there some kind of licensing headache w/the Lunceford Deccas that goes beyond Universal? Maybe one of us should drop Stamford a line & find out for sure...
PFunkJazz, there actually is a Johnny Smith Mosaic--unless you're referring to recordings he did for other labels.
In addition to the many excellent suggestions already made, I've been lobbying for a Herb Pomeroy Big Band Select, covering the four EMI-owned albums that he did in the late 1950s:
1955 Jazz in a Stable Transition
1957 Life is a Many Splendered Gig Roulette
1958 Band in Boston United Artists
1958 Detour Ahead United Artists
E-mailed this suggestion to Mosaic, and got a reply from MC saying "Risky, but tempting." Hope they decide to take the risk!