Your one just curves from the looks of things Rowan, mine literally has a bump towards the centre, so the middle keys are half an inch higher than the outer Q A Z keys.
It's this thing:
http://www.cc.gatech.edu/~eugenem/rsi/ms4000.jpg in case no hot linking.
One thing pisses me off though with it, there's no full media keys, so you have to assign the web or search button to be "Stop Music". Bit lame.
Jeez, slow day in here, I'm even boring myself.