Just wondering: she's kind of young. What are your goals for testing?
By this, I mean, most people here typically use test scores to gain entrance to various programs such as CTY, DYS, or school gifted programs. But your daughter is too young for these programs. So what do you hope to gain from testing? You already know that your daughter is very bright, pediatricians have also noted it, and you know what levels she's working at. What will testing add to that?
Not to mention that she could be too young. My understanding (could be wrong) is that testing before age 5 or 6 is unreliable, PG or not. Sometimes little kids just won't cooperate for the simple reason that they're little kids. I've read about this idea and have even heard about it happening from a couple local parents who got their preschoolers tested.
Have you considered contacting a couple centers that do testing (perhaps even Dr. Ruf) to ask about the benefits and downsides of testing a child who's so young?
Just my 2c...