Mosiac Mama,
I don't know if you can find a tester who will come to the house, but that could be key. In the meantime you can use the Ruff estimated levels and see if that gets you anywhere - don't use them to determine that she isn't gifted, just to support your hypothesis if she does have that particular set of experiences.
I would try to invite a gifted high schooler to come over for a visit (pay her as a 'mother's helper - don't leave the house, just try to get some paperwork done.') See if DD talks to her or treats her as a teacher. You can also try afterschooling with DD, nothing 'proves' giftedness than a child enjoying material that is a few grades above the readiness level of her agemates.
You can also try to arrange playdates with other gifted children - there are tales of very very shy kids snaping right out of their shells when they finally met other gifted kids.
Best Wishes,
Grinity
