Maine Coons are stunning creatures and usually large with a lot of fur. Grooming is a problem if she is not taking care of herself. Sounds to me like she may need some Prozac .
She has been rehomed so many times because of temperament??? Are there other health problems that exist?
So for 5 years you have been having her groomed under sedation?
If that is the only problem she has ( Not wanting to be groomed or touched) I would try the Prozac first.
Here is what is going to happen if you take her to a No Kill shelter. Yes there are some very compassionate ones , we have one in Florida that has had cats there for 15 years, but these are far and few in between.
She cannot be place in the general cat room--the trauma would be too great--so she would have to be given to a foster from the shelter that work with abused and traumatized cats. That is your best bet. I would ask until you find one that will allow a foster to take her. Then I would get the name and address of that foster (pretend you want to just see her from time to time) but what you must do is check to see she is in a healthy enviorment.
Unfortunately the abuse , rehoming, and trauma occurred at the hands of some evil humans. I only hope their punishment fits the crime in the afterlife--Karma is a *****.
I know this is breaking your heart, so try the Prozac first. Then ask your Vet if he would be willing to allow her to be an office cat. or if he knows someone good with these types of cats. Last resort is a foster home affiliated with a NO Kill shelter.
Be cognizant of the fact that NO KIll does not mean they will not Humanely euthanize for the cats own relief. I know it seems unfair but cats with health and behavioral problems are lifers and it is not a great life in rescue, and many rescues feel they are keeping other cats who are adoptable out of their shelter because the problem cat is taking up the space.
The world just ***** sometimes and you unfortunately have known this for quit a while. Sometimes I wish we could marry cats, they are much better than many humans.
Please know you have nothing to feel guilty about, you tried when many others did not care. This makes you very special. I hope you will feel at peace with whatever decision you ultimately make.
Please let us know what happens.
I hate to see her have to be rehomed again. That poor baby has been through so much. This is just so sad.
Try doing some research on your computer. There are lots of no-kill shelters in your area that you can call. I'm sure that a shelter will show her compassion and take her in.