What could be the main benefits of Ternary vs. Binary computing in real world applications?
[1] Hayes, B. (2001). Third base. American Scientist 89: 490-494 (http://lrss.fri.uni-lj.si/sl/teaching/ont/lectures/third_bas...)
Anyway, if ternary is actually optional in practice depends as much on how efficient the ternary logic can be implemented on a silicon process. If you increase integer storage efficiency by 10%, but circuit density decreases, maybe you're not getting enough value.
By the time someone built a base 20 computer it would probably be an anachronism anyway.
It's true that you can conveniently represent the numbers by using integer powers of the base (like representing binary with hexadecimal), but the whole reason e is a "good" base in the first place is because you're (partially) minimizing the number of distinct symbols needed to represent a number, and you lose that once you go to a higher base.
Plus, using a slightly-off integer like 7 breaks the integer-power-mapping anyway.
[1] x ^ (N/x) for any N.
Don't know if any of that has made it into the literature, but you could have a look.