Have you given ASFs a try?

Also you could try filling the tubs with "cage clutter" which can be fake plants or the cheaper alternative...crumpled up paper.

I know the feeling. I had a pastel who only ate maybe 5 times in a year. I finally gave in and got a breeding trio of ASFs and just having them in the room was enough to get her back on feed. She has been eating weekly since I brought the ASFs home (haven't fed her one yet though)