It looks like 'Ichi-ki-kei jiro' would be the best choice in a small, self-fruitful oriental persimmon (non-astringent) for zone 6 (NJ).

Some sites say it grows to only 8' and others say 10', but another says 20' tall and 6' wide.

1.If left unpruned for a decade or so, could I get it to grow around 15'?

2.Would this be the closest, taste-wise, to the common tomato-shaped persimmons in the store (i.e. brand: 'Sharon'), for zone 6 in trees smaller then 20'wide?

3.How many pounds of fruit does a mature 'Ichikikei jiro' produce?

This sounds like a very small tree/and the same in terms of production.

Thanks,
Steve

That is what I grow in Crystal Springs, MS. My trees's are only 3-4 years old, approx 6 feet tall. My step-dad's are lots older, but still only 8-10 feet tall. Very good producer's, excellent fruit.

You might want to look at the fruit and orchards forum
My mom was japanese, they have Ichi's and Fuyu's. I think she liked the Fuyu's the best. He also has Tanenashi.