The difficulty with this question is that there have been so many children's books that combined the stories of Münchhausen, Till Eulenspiegel and Die Schildbürger. Below are a few examples, each of which is a hardcover edition. (I have not included the links to Amazon.de, since these will become invalid over time.)
(1) Die schönsten Vorleseklassiker: Till Eulenspiegel, Münchhausen, Rübezahl, Die Schildbürger. Vorlesebuch und Geschenkbuch, published by Gondolino in 2013 (but this may be a reprint).
(2) Narrenstreiche - Münchhausen; Die Schildbürger; Till Eulenspiegel - Drei lustige Erzählungen, für die Jugend bearbeitet von Friedrich Hanke, published by Verlag Jugendhort in 1920. See the bookcover below.
(3) Till Eulenspiel & Münchhausen & Die Schildbürger, edited or retold by Kurt Eigl and illustrated by Ernst Schrom, published by Bertelsmann in 1962. See the bookcover below.
(4) Narrenstreiche. Münchhausen. Die Schildbürger. Till Eulenspiegel, edited or retold by Hanke and illustrated by Hanetzog; published by Jugendhort in 1910 (some editions of the same volume were published earlier or without a year of publication). See the bookcover below.
(5) Erich Kästner erzählt: Münchhausen, Gullivers Reisen, Till Eulenspiegel, Die Schildbürger, Don Quichotte Cecillie Dressler Verlag, 1975. See the bookcover below.