Jamie,
 
I also have a (reformed) bad biter, though I don't know if my experience
will help.  I got Lexie secondhand when she was 2.5 or so, and she was
just a biting monster!  She was playful and in many ways sweet-natured,
but she'd bite anyone, any time, with no provocation at all.  And these
were some hard bites - I did get red scratches and some blood from time
to time.  It was a very frustating experience to have this really nice
little ferret who was completely unpredictable and unsafe around
strangers.
 
The good news is, she's largely reformed now.  I mean, she bites the
occasional toe, and is not above nipping (I think she bites everyone she
meets just once, out of habit...:)  But by and large she's a much *much*
better girl than when I got her.
 
The bad news is, I can't explain exactly how that happened.  I did all
the tricks - saying no, scruffing, biting back a few times - but it
really just took a long time, a lot of patience, and my resisting the
urge to make her into a hat, that did it.  I'd say it took about a year
before she showed significant improvement, and she's gotten better and
better over time.  I still tell people she's a biter, but the bites she
deals now are quite gentle, really.
 
My only experience is, time does matter.  Also, on a practical level,
I've found it hurts less if you don't pull away from the bite - with
Lexie, if you pulled away she'd just dig in so you couldn't get loose!
I scruff and hold my hand in her mouth until she lets go, then tell her
no and put her down.  And sometimes, the biting was definately a "Hey,
pay attention" move on her part, so I'd try and make sure to pay
attention *before* she got mad about it...:)
 
You also said you were afraid nobody would adopt a biter - but there
are suckers out there like me, who will take in the hard cases and just
suffer the consequences...:) So do try and give her up to a shelter (if
you have to), rather than put her down - there's always hope for her
that way.
 
Good luck!
Megan and the terrible trio:
Lexie ("Hey!  Stop talking about me!")
Sammi ("Well *I* never bit anyone!")
Trixie ("It's okay to bite raisins, right?")
[Posted in FML issue 3801]