He's gotten very brave and curious now. He still hisses when a new person enters his enclosure, but I believe that's his prerogative since it's his territory. He's gotten tame enough, though, that volunteers have started taking sleeping bags and spending the night with him. So far he doesn't sleep WITH them, but soon he will grow used to them and he'll be happy to cuddle up.
I leave a week from today. You can't imagine how much I'll miss him.