Um, you can't play a practice match using the shot..? Or play some practice points? I mean what the hell are you at an academy for? Saying you've practiced against such a low-percentage shot against the wall and then talking about it, just a waste of time
As far as unique shots go, well, if it is unique, in general you won't be finding anything "truly" unique. I guess if I have to speak personally, the one shot I sometimes hit, is a overhead where I nearly get on my knees to hit if the ball doesn't bounce as high as I thought. I saw Baghdatis play such a shot several times especially at Wimbledon 2006 and I have used it a couple times to decent effect. Tough to pull off, especially since it has to be off a bounce that isn't too high and without too much forward momentum.