Heres a review of the iControlPad working with the Samsung Galaxy Tab 7.7/ Shows you can use this type of controller and possibly others:
http://www.mobilelinuxnews.com/2012/05/review-icontrolpad-samsung-galaxy-tab-7-7/
http://www.mobilelinuxnews.com/2012/05/review-icontrolpad-samsung-galaxy-tab-7-7/