Define a bit of code that names all our class constructors based on the property name under which they were stored, and use that in Item#toString().

src/item/Item.js

@@ -1589,7 +1589,11 @@ var Item = this.Item = Base.extend(/** @lends Item# */{
 		},
 	*/
 
-	// TODO: toString
+	toString: function() {
+		return (this.constructor._name || 'Item') + (this._name
+				? " '" + this._name + "'"
+				: ' @' + this._id);
+	},
 
 	statics: {
 		drawSelectedBounds: function(bounds, ctx, matrix) {

src/load.js

@@ -129,3 +129,12 @@ for (var i = 0; i < sources.length; i++) {
 			+ sources[i] + '"></script>');
 }
 
+// Append a bit of code that names our classes.
+// See src/paper.js for an in-depth explanation.
+document.write('<script type="text/javascript">\
+Base.each(this, function(val, key) {\
+	if (val && val.prototype instanceof Base)\
+		val._name = key;\
+});\
+</script>');
+

src/paper.js

@@ -122,6 +122,15 @@ var paper = new function() {
 
 //#include "core/PaperScript.js"
 
+// Iterate over all proced Base classes and set the _name property of their
+// constructors to the key under which they are stored. This is a simple hack
+// that allow us to use their names.
+// Setting Function#name is not possible, as that is read-only.
+Base.each(this, function(val, key) {
+	if (val && val.prototype instanceof Base)
+		val._name = key;
+});
+
 // Finally inject the classes set on 'this' into the PaperScope class and create
 // the first PaperScope and return it, all in one statement.
 return new (PaperScope.inject(this));