I guess the problem you will have is that anyone with a Sohal, that is peaceful, probably won't give it up. I myself, have a very peaceful one overall, therefore it is the showpiece of my tank. Only way I will give it up, is for alot of MOOOOLAAAAA.
Good luck finding one, I hope you do. I guess the problem overall is firstly getting one that is peaceful, but more importantly if you do find one that is proven to be nice, once transferred to your tank, will it stay that way. Cross your fingers on that.
But I will say, I do love my Sohal and would recommend them, but buyer beware!!!!