So glad to see you guys working on this new control!!
We are currently using the project at http://slg40.codeplex.com/
for our property grid. One of the nice things about it is we can develop custom dialogs/editors for properties. For example, we have a hierarchy of busines divisions/groups/teams containing hundreds of nodes. We can create a custom dialog to let the user drill through a RadTreeView hooked up to a web service using LoadOnDemand to find a particular node. We can then have a property of type Team, and tell the property grid that objects of type Team should use the custom editor.
Another property editor we need is multi-select. In the Attribute declaration for the property we could specify a delegate to return a List of objects, and the property editor would basically look like a multi-select combo box. We can code this up ourselves if necessary, we just need the attribute support baked in.
Would love to see you guys get custom editor support in your PropertyGrid!
We love using your controls!