I'd look at these. http://www.frioinsulincoolingcase.com/

They are kind of boring but she might find a designer looking pouch at nickisdiapers.com. They stock Planet Wise bags which come in a bunch of design options. I'm guessing that a wipe pouch or small wet bag would be the right size to fit a case. They also have insulated lunch boxes. Use coupon code FIVE at check out for 5% off.

You might also look in etsy.com. You may find something she likes or someone who would make one to her tastes.