How is continuous play with song cues in mixtapes handled in iTunes?
Jason Salaz, lost my cookie :). Yes, cue sheets are mostly (entirely?) format agnostic but their usefulness depends on the player, as it's the component that adds cue information upon playback. In case of iTunes it appears that Apple embeds this information as metadata in a m4a container. 

I tried using GarageBand to do this upon your suggestion, and it created an m4a file with embedded cue data. However GarageBand does other unrelated work, like reconverting the audio, normalizing and so on. I found an audio book editor on the Appstore that may do what I want as well, or perhaps a m4a metadata editor will as well if I find one.