By popular demand (okay, 2 people asked), you can now browse or clone the inscriptOL repo. I need to get back to the GIS-y aspects of Pleiades and won't be actively developing inscriptOL for a while, but patches are very welcome. SVG.js needs to be extended so that the format supports points and polygons as well as polylines. OpenLayers.Format.GML was my starting point and the difference between the polyline methods in the files should be illustrative. Code to browse and select source imagery, with setting of bounds and dimensions to appropriate values should also not be much of a task. Sound support for editing traced features is the most complex of the first things that need to be done to turn this into a serious tool.