I think the far end of the keyboard we use at work is raised almost... 5cm, or so. But it's also arched up towards the middle, as well as being split. Trust me, It's Good For YouTM. Not the same keyboard as the one in 40Hz's post, but more or less same principle (although ours are more flexible).
You do need proper chair and table adjustments and sitting position before it's comfortable to use, though. But you need that anyway, unless you want to trash your body sitting 8+ hours in front of a computer every day. oh, and you need proper arm rest. If you don't have your entire lower arm supported on your desk, then that's not exactly good ergonomics either. You might not feel the effects now, but wouldn't it suck suffering from carpal tunnel and/or discus prolapse (dunno if that's the right English term) when you're 30?