Or describe what has to be done.
May be someone reading may want to participate.
One related area is Ivica's K12 module in Pd-l2ork. That is something I haven't ported yet. It could probably be implemented using data structures, but I'd bet it would be a lot easier to just use an HTML template to display a column with a menu next to the patch. So a solution to that probably looks a lot like the solution to your feature request:1) How to add HTML above/below the Pd canvas SVG in a Pd patch. This probably requires changing some code in the mouse event handlers which currently deal with pageX and pageY coordinates. If arbitrary HTML is surrounding the SVG then we'll have to use a different way to figure out the mouse coords relative to the SVG instead of the document.2) How to use that template instead of the default pd_canvas.html template in pd/nw.3) How to create and open an arbitrary html template using the Open dialog4) How to refactor anything that currently depends on the Pd canvas SVG being the only visible element inside a patch window.
That's probably a good start.
-Jonathan