I love kei cars like the Beat & the Cappuccino. I'm tall & fat and will never fit comfortably in one.
I couldn't fit in my brothers MR2 spyder, and I don't think I could fit in a miata unless the top was down.
MightyCarMods has done a number of episodes and even a couple of full length movies about little JDM "nuggets".
As far as people recommending a miata, realize that these key cars weigh around 700-800 pounds less than even a miata .... (though most people who shop for those things will settle for a more "rational" or at least easier to live with Miata.. or a used mr2 if they can find a good one)
You like the "idea" of Kei cars, but admit that you could probably never deal with the "reality" of driving one.
This is the perfect support of my novelty argument.
Sure there may be some fringe of Kei fanatics that would put up with the multitude of drawbacks and stick with it long term.
But I would argue that most, you and the OP included, are simply in love with the "idea" of a Kei car, but the reality of owning one would soon wear thin. It's a novelty experience, with a huge amount of drawbacks, and the novelty will fade quickly and the drawback will always be there.
Through ownership of two Miata's I have never once thought. "Gee, I wish this was even smaller and less practical", though I have thought the opposite often.
I would argue that a Miata has about 90%+ of the benefit of a Kei Car, but less than 10% of the negatives.
Almost anyone considering a Kei car should spend some time living with a Miata, to see if they still think the want something a lot smaller, and more impractical.