I know you said you tried everything but I'm still going to ask ...

Have you done a food trial to see if she's allergic to wheat, corn, soy, or meat in the food she's eating? Mandy and Nova both have food allergies and get chronic ear infections with meat and Nova also gets rashes on her belly.

IF you have done this then you may want to flush her ears, instead of just clean them. It will get further down in there than just cleaning them.