(I use an Android, but you can probably get this on an isuckPhone.)
There’s a keyboard called iKeyboard. I originally downloaded it for the emojis, but when the theme I chose (Halloween, of course) changed the font to one that was hard for me to read, I found an interesting theme I didn’t know existed: create your own.
You can choose a picture from your gallery or use a new one. You then choose the color the keys will be. And, voilà, you can have a keyboard with your kid’s face! Or your exes face, depending on how you look at pressing / hitting the keys on your keyboard.