add switch_theme capability to contributor

Hi – first post and new to this great site – have learned a lot so far by lurking but need advice as to accomplish this task.

How can I tweak a user role to include a specific capability not inherently assigned to it? For example – I want the contributor level to be able to switch themes, would prefer to disallow the submenu(widget,theme-options, etc) if possible. Played with schema.php, menu.php but no dice – am I close?

Seems like there a many plugins and tips on issues very close to this – dsaders menus plugin, adminimize are close.



ps – if you are wondering why, we are rolling out about 500 student blogs next week to student K-8 – assigning them as contributor but they will of course want a little creative license with their site. thanks for releasing batch create!