This level of integration with the project explorer is difficult, as it would need to consider other VS plugins that may also make changes in this area ... also, anything that involves close integration with VS does tend to take 10x longer. Likely this would need to exist as a separate tool window, though there are other things that could also be bolted onto this to make it very valuable as a feature. Thanks for the ideas - I'll see what I can do :)
Cheers,
Remco