Music sites usually have midi keypads for loops, etc, which sill probably meet yoiur needs.
http://www.guitarcenter.com/KORG-NANOPAD2-Slim-Line-USB-Drum-Pad-Controller-106870629-i2618515.gc
or
http://www.guitarcenter.com/KORG-NANOKONTROL2-Slim-Line-USB-Control-Surface-106699283-i2618519.gc