Hello!
The character's name you are thinking of is 
Hinase. Yep. Just like Minagi's ship in the manga.
Tee hee hee. Also, her character design is based 
on
Tokimi from the OAVs (in much the same way as 
the character design for other characters is 
based extremely loosely on the OAVs).
Actually, she's one of the few Shin characters
I've seen who are drawn interestingly at all.
As such, I suspect you'll pay a bit more than 
the others. I really don't like the art in Shin
at all, but there are a few nice bits. 
I have never seen one however. I recommend getting
a screen grab and mailing it to dealers who
want to know what people are looking for.
Otherwise they might not know what you're talking
about!
There are bound to be a few cels of her about.
Good  luck!!
Ryochan
(who is still desperately looking for cels of 
Tokimi from the OAVs)

p.s. Go buy or rent the Tenchi OAVs. CN butchered
them and they are worth seeing in their uncut 
form.