Intriguing idea for a thread. I like a lot of Kyo's and TMG's suggestions. Right now all I can think of is Louis Smith's two BN albums on one disc: Here Comes Louis Smith/Smithville. Haven't computed playing times, but I'd be surprised if these added up to more than 80 minutes.
As for "2 on 1" CD's that have already been done, I'm particularly thankful to 32 Jazz for 'single-discing' two of Sonny Stitt's best albums, Tune Up and Constellation. Of course, it's out of print now, but still... And perhaps my favorite Benny Carter CD (which is saying a lot) is the Verve reissue "3,4,5"---two albums and 3 bonus tracks. (The trio album has Carter playing with Teddy Wilson and Jo Jones; does it get any better than that?)
Then there's the wonderful Stuff Smith double-disc set from a few years back that is in effect "3 LP's on 2CD's." For a while Verve was cranking out several of these "3 on 2" sets...And there's Sonny Criss: The Complete Imperial Sessions, an essential 3 on 2...but maybe we shouldn't get into that right now.