I don't know if anyone has tried it, but for the most part the advice from the softcore thread should apply; you'd probably err on the side of survivability, however.
I remember a post somewhere where someone pre ROS had done WDs on hardcore, though.

I don't know if Crusader's have a 'get out of death free' card though.

One general caveat to multiboxing in hardcore is, sooner or later, you are going to get scattered. Imagine vortex + twisty blind corners and things to get stuck on + movement effects and mob packs and trying to group up 4 characters. Most of my death's in softcore originate from this sort of thing. Something to consider, before investing a lot of time/effort into multiboxing in hardcore. If you do box, I'd be extremely conservative in terms of what difficulty level I fought at to minimize this effect.