I found this article which contains a review of the Harmonix. The author (who appears to be a compulsive purchaser of harps - or at least has a huge budget) was not impressed ...
I saw a video (well part of it, every five words or so it had to reload) for an electric turboharp where the guy held the harp in front of his amp and blew into the harp from over a foot away and got a tone and no feedback.
i indeed have thought of this alot. i play harmonica in my hair metal band, actually.
ive also thought of how to make a versitle harmonica mic-ing system, because im pluging in my harmonica to a guitar amp, so i can add distortion, reverb, etc.