Pretty awesome! If I ever had to say the one thing that differentiates successful people from unsuccessful people it wouldn't be intelligence, or even perseverance, or passion. It'd be focus. With focus, you can be amazingly successful in so many types of occupations.
(That being said, passion / perseverance / intelligence can often lead to focus)
Are these even legitimate? If a person can paint a masterpiece but can barely balance their checkbook, IQ tests won't show their mastery in painting, only their mediocrity in math.
The argument you're making has often been made as "there are different kinds of genius". The research seems to have debunked this. Rather than seeing multiple ways to be a genius, we see some general intelligence ability that helps you no matter what you're trying to do.
In the case of our painter, if we're talking about Michaelangelo or something, he'd likely come out with an excellent IQ.
As an aside, IQ tests don't try to make you do math problems and the like, it's all pattern matching kinds of questions where you learn all of the necessary context in the test itself. Which makes sense right, it's trying to measure your ability to learn and generalize, not what you happen to know before you take the test.
However you're defining focus I'm sure correlates pretty well with the personality trait conscientiousness. (IQ is the best single-variable predictor of nice things like life success, for various definitions of success, IQ + Conscientiousness predicts even better...)
They're not called that, but they do exist. I recently went through a full day's testing for issues relating to autism and a number of the tests related to ability to hold focus rather than skill, per se.
One I recall vividly was basically a page full of weird symbols and a "key" at the top mapping symbols to numbers. I had to go through the whole page converting the entire page and various elements of my performance (variance of speed, attention, etc.) were measured during the task. This does not really correlate to what I'd consider focus or "flow" during typical programming tasks, however, but it did try my patience! :-)
(That being said, passion / perseverance / intelligence can often lead to focus)