Francois,
I like the way that you've coded this up, but there is a minor yet major point you've missed.
Although this will work great for things like numerics and such, things that have hierarchical layers of properties will fall very short.
I've been trying to eat the beast from the inside in order to make this possible through scripting by being able to get the full hierarchy of properties exposed through VI Server, but have fallen short so far.
There are a few classifications of property 'types' that warrant having some time spent defining.
I really think that an waveform graph is probably the most inclusive of all types and also the one that needs this ability the most (think XControls)
Unless I really mis-read your code, and it actually does this exact thing.
(if so, feel free to steal one of the beers that I've got lined up for me @ ni week this year)
-Norm