A little while ago, I spent some time investigating UI approaches for representing sequences of sounds (or other media queues) on a freeform timeline (no time ruler). In the process, I came up with a couple of JSUI gadgets that, although I never ended up using them, I thought I should share in case they were useful to someone here. If nothing else, there is some hackable JS code in there for dragging behaviors, saving JS data to a dict, and using mgraphics to build a minimal UI. I didn't go to any extra effort to make comments or clean these up, but the patches and code should be pretty self-explanatory and easy to alter, I hope. Let me know if you find these useful or have better ideas.
playlist.js - pretty straightforward timeline UI with ability to overlap blocks
playlist_triggers.js - represents the same playlist as buttons.
playcluster.js - inspired by the buchla sequencer, this UI snaps blocks end to end and allows for dragging out the length of block or dragging to rearrange.