This just in from Jim Korkis:

[I think your Christmas listing of what you want Santa to bring should be a regular feature on your blog: Lost Treasures (that need to be found).

Here's my first contribution:

In 1929, the Disney Studios made two speciality films with Mickey Mouse. One of them is well known and copies exist: Mickey Mouse singing "Minnie's Yoo Hoo" with some reworked animation from "Mickey's Follies" as a sing a long for the Mickey Mouse Clubs that were in theaters at the time. The second may be one of the most rare Mickey sound cartoons and while there is documentation that it existed, no copy has turned up so far. Again, this was made for the Mickey Mouse Clubs. The film combines animation of Mickey and Minnie with live action of vaudeville star "Noodles" Fagan. I am not sure what the content is but judging by the fact that it was for the Mickey Mouse Clubs it may have involved some type of audience participation, perhaps another sing along.]