Firstly, I don't know which preschool teachers you know but I can't imagine many of them caring about a WiFi signal strength checker (it is already built in), porn (iPhone websites already exist and you can put your own videos on the device) or installing apps from outside the app store.
Secondly, you seem to be ignorant of the Cydia App Store where there is a large number of paid apps for the more power users.
Secondly, you seem to be ignorant of the Cydia App Store where there is a large number of paid apps for the more power users.