The Stealth KYBX-400-DT-BL-TB-USB Keyboard (that's quite a name to remember) is sealed to the NEMA 4, 4X, IP65 specifications (these are two different test grading systems, that's all I can say). But it's rugged enough for military use, so it will easily do the job against pets and small children. It is housed in a rugged vandal resistant stainless steel enclosure, has an optical trackball and features adjustable backlighting.
But this comes at a price - $695. So some strict discipline and patience with your child can be a whole lot cheaper alternative.
