I already wanted a tentacle back in April, after watching District 9 as prosthetic arm / prosthetic hand. Tentacles are prosthesis are not available so far. So we would be looking at a new general idea here.
Now, a new design is out.
I want one like this badly, I really do:
Kaylene Kau designed this as supportive device for a dominant hand. As that, it does have a lot going for it. And before wasting time on theory and on explaining why - I want to try this thing out.