Thanks for this utility, my Daughter really like it for painting her kiddy pictures.
One cool feature could be to tie up paintbrush with iPhone/iPad via BT or WiFi and to use the "i" device as a kind of pen tablet, using finger instead of a pen.
I think I know what you are referring! Have you heard about this accessory of iPad called nomad brush? The said accessory will develop the creative minds of the youngsters plus it also serves as a learning tool for budding artists testing out and refining their skills. Now, that sounds really fantastic, isn't it?