I'm not 100% positive that this scenario doesn't exist. All the combat dummys i have found exist in a space where combat abilities and buffs don't fade. I have tried test, where you spawn one in the arena, but iirc , the buffs didn't tick down there either. Is there a way we can get one (if one doesn't exist), either on live, or test ?
The dummies in the arena on test respond to the "freeze buff" and "unfreeze buff" commands, so you can choose whether or not your buffs fade. Those arena dummies are kind of outdated now, though, which matters for melee parsing because their defenses are terrible and because you can actually kill them with enough DPS. It would be really nice for GGH dummies to have the same feature.
please, should any of the Powers That Be skim this thread : PLEASE have the next generation of Guild Hall Combat Dummy come built with a real AC number