The author of the book Face Food: The Visual Creativity of Japanese Bento Boxes (my review here) Christopher Salyers, has an excerpt of the interview he did with the one father/bento creator that appears in the book.
Takupapa (meaning the father of Takkun, his son's nickname) started making cute kyaraben for his son when his wife was hospitalized. Quoting from the interview:
What is Charaben to you?
Charaben is a collection of precious times I spent with my son. Each and every Charaben has an episode, and I hope they will become good memories when he grows up.
And here's the link to Takupapa's bento blog (in Japanese). Takkun has one year left to go in kindergarten, and Takupapa plans to continue making those cute bento for him until he enters first grade in the spring of 2009.
(Incidentally, someone asked me if there is a difference between charaben and kyaraben. There isn't - it's just two ways of spelling out a Japanese word. The original is キャラ弁, and it's a combination of キャラクター (character) and 弁当 (bento). I prefer the phonetic kyaraben, since I keep reading charaben with the ch part pronounced as in chair.)