It's probably a complete waste of Gallade's offensive abilities and other Pokemon can pull the same set off better, but he's capable of running a pure utility/support set in Doubles/Triples.
Gallade @ Leftovers
Ability: Steadfast
Bold / Impish, 252 HP / 252 Def / 4SpDef
-Trick Room
-Imprison
-Protect
-Helping Hand / Shadow Sneak / other
I mean seriously, how many people are going to expect Gallade to be a Utility Pokemon? He wouldn't be very high on my list of Pokemon to hit with a Taunt.
Imprison + Protect is a very mean combo in Doubles/Triples, since as long as it's out, no opposing Pokemon can use Protect. That followed by Helping Hand often spells doom. If a non-attacking Gallade isn't to your liking, use an Impish nature and Shadow Sneak or another physical attack. Trick Room is there to help set it up, as well as Imprison it.
EVs are to provide Gallade with as much physical bulk as possible, since it desperately needs it.
The reason to use this over Musharna (who can pull this off with Telepathy) or Cresselia (a very, very well known utility Pokemon) is that it's unexpected; most opponents will expect an attacking Gallade, and not a defensive/utility Gallade. Gallade also has a secondary Fighting type, which renders Bug and Dark attacks neutral (which helps survive many attacks better than the previously mentioned duo), as well as it's somewhat higher base speed for helping get off an Imprison first (outside of Trick Room).