I love that Ranma OVA too! :)  I have seen cels of
the "evil" Akane for sale around the web, but not 
in a while.  I have a Ranma from that OVA that's 
quite nice.  You can see it and a screen shot at
http://www.jenorama.org/cels/newranma.htm.  If
you're looking for "evil" Akane cels, look for her
in the dark blue yukata and the pink bow in her
hair. :)

Jen