Try putting it forward as both Art and IT, All you have to do is buy graphic tablets so Arty people can draw (wacom Bamboo fun) these tablets are great and not to dear either plus you get Adobe elements with them.
Also boot camp them with XP and IT can use them, or if IT are feeling adventurous don't boot camp an iwork site licence for a K12 school is only ?155 + ?10 for media.
Lastly if you are an integrated school with a primary school you will have access to the ELF (education learning fund)