L. Frank Baum was clearly a master of self promotion, and of the "story that suits the moment" style of interview. Consequently, I tend to take most of his statements with a large grain of salt. A fun example of this is an article published in the August 1909 issue of The Theatre magazine. Titled L. Frank Baum and His New Plays, this interview covers Baum's then-current theatrical projects, none of which were to make it to fruition.
According to this article - and this all sounds very optimistic, as the descriptions of the various projects are very vague for shows opening in a month or two - the fall season was to see a comic opera titled The Pipes o' Pan, an extravaganza titled either Ozma of Oz or The Rainbow's Daughter, and the opening of a new Children's Theatre in New York. Another comic opera, possibly titled Peter and Paul, was being written for Montgomery & Stone. Both this piece and the coming Ozma of Oz were said to be starring Montgomery & Stone, so there would seem to be a conflict!
Ozma of Oz did finally see production in 1913 as The Tik-Tok Man of Oz, which played in Los Angeles and toured. However this is not quite the same show described in the article - for one thing, a different composer wrote the music, and Montgomery & Stone were nowhere to be seen.
Baum does discuss Oz as well. He manages to add a year to the run of The Wizard of Oz - the show started in Chicago in 1902, and here in 1909 Baum states that it has been running 8 years. At the time of the interview, Baum also mentions that he is working on The Road to Oz, and that there will be only one more Oz book.
But the part I like best about this article, is the correction that the magazine had to publish in the next issue! While talking about the possible Peter and Paul production, Baum mentions that the music is being written by Arthur Pryor, the famous trombonist who played with John Phillip Sousa's band. Baum is quoted as attributing the success of Sousa to Pryor, something which apparently did not go down well. In the next issue of the magazine a correction was published, including a letter from Pryor expressing his astonishment at Baum's statement. The magazine wrote to Baum for an explanation, but there doesn't seem to have been a reply....perhaps this contributed to the non-existence of the Peter & Paul show!
The full article can be read here, on the Hungry Tiger Press website.