Daniel it sounds like you need to read
The Myths of Innovation by Scott Berkun. I got the recommendation from JVN's blog. There are many innovations, yet you have to open your eyes to see them and appreciate them.
357 poured their own linear slides in 2007. It was innovative enough to patent it. Or was that their battery mount, which is now
a product?
To me, 1114's ball launching idea for 2008 was innovative since it not only did what others thought impossible (punch the ball over the overpass) but it also did so in such an elegant design that I'm surprised the design itself hasn't received more attention. Everything fit together so well that year on that bot.
For drive train, there's 148's nonadrive. Yet the innovation really comes from the whole design, which JVN explains on his blog. Not only is it a defensive drive train, but it's an anti-defense drive train as well.