So, I was just watching Andy Serkis on TV, talking about how he has played gorillas and chimpanzees in various films. Part of the secret is the use of arm extensions - short, rigid stilts which are worn on the forearm to give extra length.
In films, these arm extensions (along with the rest of the
actor) are used for motion capture, and the body of the ape is then animated over the captured motion. All well and good, but.
Proposed, heretoforthwith, are fully functional arm extensions, for both cinematography and personal enjoyment. The wearer's forearm fits into a cuff at the top of the extension, and his (or her) hand fits into a gauntlet, which lies within the faux, elongated shell of the forearm. The gauntlet, of course, is connected by wires to a replica hand at the end of the device.
As a resulting consequence (as [Ian] would doubtless certainly say), the false hand at the end of the elongated arm can function precisely like a normal hand. Wrist movements can also be captured and faithfully relayed.
All that's lacking is sensory feedback. One simple way to give basic feedback would be to have water-filled bladders on the false fingertips, connected by tubes to corresponding bladders in the gauntlet. In this way, pressure on the false fingers would be relayed directly and perceived as pressure on the actual fingers.