Wolfie,
 
I have deaf biter.  After bout 9 months, she no longer bites me at all but
does bite others I hate to say.  I took it in stages and had several set
backs too.  First step is to buy a set of nice leather gloves.  Use them
both when handling the biter.  You might also use bitter apple along with
it, but I didn't.  I scuffed her when she would randomly bite (as compared
to play biting).  I had a time out cage too.  But I spent allot of time
with her playing with her and touching her.  First with the gloves, then
with a towel (she loves to play tug a war and hide and go seek with it).
When in the towel she would gets lots of pets and rubs, she became more
and more used to being touched that way.  Also, if she were in hammock
I'd lighting touch the underside of the hammock, again so she'd get used
to being touched in a gentle way.  Soon, I went to a single glove.  I'd
control her head with one hand then gently stroke her with the free
ungloved hand.  Later I went to no gloves, but always was careful of where
her head was and to control said head when I handled her.  If she got
nippy she simply did not get attention at that point and she quickly
learned that if she wanted pets, rubs, kiss's ect, she had to be very
nice with my hands and feet.  On the good side though, she never bit at
my face so she always got and gave kiss's, even at the worst of times
(like when she lost her best friend/cage mate).
 
On the downside, because of the biting I have never really let anyone else
handle her, so when people now want to handle her she bites (mostly women
for some reason).  She's always been rather dominate, so I always think
in part that this is her dominance playing out.  As I'm her Alpha, she
wouldn't dare do that to me.  She also still gets a bit nippy when she's
playing hard, but I expect that as she's a ferret and it doesn't hurt
like the biting did.
 
Hope that helps?
[Posted in FML issue 3765]