Years back, I picked up this cel off ebay. It turned out that the person selling the cel lives in the town where I work, and she even had friends at 3DO! So, not only did I end up with a great and fairly rare cel of Akane in her long-hair days, but I also got to meet a very nice young woman who let me look through the rest of her wonderful collection of Ranma cels. It was the best ebay experience yet!
02-18-2010 - I finally found where this cel came from... its from the 6th ep. of Ranma... "Akane's Lost Love... These Things Happen You Know". The cel appears about 16 minutes into the episode, just after Akane and female Ranma share some burgers in a park.