Anyone figure out how long it takes for the deposites to respawn yet? And on another note, am I the only one who mines these things half expecting and half terrified that after I've mined a deposite clean a draugr is going to jump out and attack me?

No idea on the time but I am waiting for an ambush

Do any ore deposits respawn? I've never actually gone back and checked.
In any case I've seen the Skaal smith sell stahlrim occasionally, so it's not like there's a completely finite supply.

Right? I know I wouldn't be able to resist putting it in the game if I was working on it.

IIRC, normal ore on skyrim respawns in 14 days or so.