Ask YC: 2D rendering method via JS?

My recent project idea requires the rendering of a fairly custom UI to mimic something similar to the interface of multi-track audio recording tools. i.e., potentially large virtual surface that can extend far in X and Y directions that is easily pannable and zoomable. (a la gmaps) and revolves around placing UI pieces along horizontal 'tracks' with the caveat that elements on tracks can collapse with other elements on consecutive tracks. How would you implement it? Something I'm throwing around: * Straight JS and a large table to add/delete rows/columns * Dynamically generated divs * Huge canvas rendering * Generate imgs on backend and update a la Google Maps (not preferable) * Use something like Cappuccino and follow AppKit-style rendering I'd love to hear your thoughts.