Although no real-life version exists, a nuclear handgrenade did make an appearence in a mission-module for the 80's pen-and-paper RPG, Paranoia. (The module in question was titled Alpha Complexities.)
Officially designated as the thermonuclear grenade, it was described as being a hard metal sphere with the with the words "THROW VERY HARD" printed on it. The GM information went on to mention that it had the same effective yield as a tacnuke, and that any troubleshooters that were desperate enough to actually test it would likely be unable to report back on its one major design-flaw (see point 2 in WWWWolf's above writeup).
As any good Paranoia GM knows, sometimes the best way to hose your players is also the simplest, and slipping a few nuclear handgrenades into their list of assigned mission equipment could always serve to liven up a dull mission. After all, as far as R&D is concerned, the device functioned perfectly: it destroyed the enemy, and they didn't hear any complaints about it afterwards.
The above information is, of course, classified Ultraviolet, and any troubleshooters without the appropriate security clearance should immediately report to the nearest confession booth for termination.
Friend Computer reminds you to have a happy day.