I've read on the UESP that the abandoned house in Markarth never respawns. Would that mean dead bodies would never despawn in there as well?

im looking for a place to store all my dead thrall corpses

Well, Vigilant Tyranus despawns, but everything else remains as it is, so I'm not sure if it would be safe for dead thralls or not.

Kill something you don't want to keep as a thrall and then stash it there.

Come back after 10 days. IF it's still there, it's safe for thrall storage,

But this thread gave me an amazing idea..