C'mon, let's be good sports!
I guess it wouldn't hurt to go in strict order of the syllabary and come up with VERY GOOD mnemonics.
So why reinvent the wheel ?
1. It was never invented quite right.
2. Like the Japanese conceptualization of civilization, practice makes perfect, and alwasy room for improvement.
I don't think this is going to be easy, but let me give it a try.
い:
Mnemonic: This is the pictogram of two hands; in English it became an "i."
Folk Origin: The left hand side is the Canaanite-PaleoHebrew "yod," supposedly "a hand," which became the Greek "iota," the Latin "i," the French "i, i-grec," and the English "i, j." It was so small that it was also called a "jot" or a "dot."
Folk Japanification: The Japanese had a better idea then the Canaanites. Every healthy person has two hands, so lets make it more representative. For the two hands, it shall be doubled and written い.