My (5 year old) daughter received Mo's Mustache for Christmas and she loves it! The book itself isn't really about (financial) Mustachianism, rather the spirit (in part) and symbolism of Mustachianism. It conveys the concept of not being afraid to stand out as an individual in your choices. I especially love that everyone wants to follow his lead, which at first he dislikes.
The Book:
http://www.goodreads.com/book/show/17262791-mo-s-mustache
Also, I'd be interested to hear about how folks talk to their children about Mustachianism, or funny stories of kids being Mustachian!
Our daughter always talks about her "Money Mustache".
Examples:
1) She loves her bank book - and loves going to the bank with her 'stash received from Christmas/Birthday etc.
2) She got a paint-a-pig piggy bank that you bake in the oven (after painting) for Christmas. She painted an elaborate black money mustache on it. It is very funny - I should post a photo.
3) She sometimes runs around the house with something above her lip saying "look at my money mustache".
