Finally I found this collar at a pet store when I was online. It is not a virtual store but it did offer online purchases. It came yesterday and I immediately make Akira wear it.
I was afraid it would be too heavy as Akira goes to Adrian for spine alignment as well as her muscles. But I saw she was able to manipulate the collar by herself and this collar does flop down on her body if she hits a wall. This means she can move around quite freely and won't be hindered at all.
This pic shows that she can sit on my lap quite comfortable and rest her head on the petals. It's also soft and pliable but not floppy. I am hopeful that we have found a solution for Ms Akira.