Pretty cool. I'm not sure exactly what you meant in the cons by not ending completely clean, but if it's not practical for close up work I'd happily put this in sort of a cabaret/stage show as sort of one of those little miracles in between the actual effects that makes your magic seem that much more real.
One question though. Could you put the case on a borrowed phone then change the color? Let's say you borrow a iphone with the intention of doing Pressure, then you say that you don't want to mess up the phone so you put on a cover. Then you say that the cover doesn't match the phone and visually change the cover and continue with Pressure. Would that be possible?
Your hands wont be completely empty is what I meant, but you can pocket/sleave the gimmick and get rid of it.
(Omg, I just realized I lied in the vid)
I had it finger palmed and let it drop off site of the camera, O_0
But I've performed this for my family and a few of my friends, I always finger palm it and then let my hands drop to my side after I hand it to them, then i just drop it in my pocket.
I suggest pocketing just because I never where long sleeves, but if you happen to where sleeves
you could attach this gimmick to a pre-existing gimmick and end completely clean.
Hmmmmmm, about using a spectators phone/ipod
With the current gimmick, you probably couldn't do it, but I think with a slight modification and a little slight of hand you could pull it off.