Green and red pads together I suspect.
What's more disgusting is that someone would feel the need to play bass at medium for, well, pretty much anything other than a very small number of songs.
We got a pretty good vocal pack this week, they need to start giving us some more good bass songs. Basically we've got Rush, The Who, Black Sabbath, RHCP (though I haven't found a lot of difficulty in the bass parts, from what I've played, at least they're generally fun to play), apparently Duran Duran is rather good on bass, but I wouldn't know myself... uh, and not a hell of a lot else.
How about some Mr. Big? Not really my choice to listen to, but Billy Sheehan is one of those bassists who really just wants to play guitar and does a lot of tapping and chords high on the neck. Not really my sort of preference (I like bass that tries to still sound like, y'know, bass), but checking out some tab I've got here it'd be a pretty good challenge.
How about... uhm... not entirely sure where to go here... maybe more prog? Some King Crimson would definitely work (Chapman Stick Hero!!!) and we could certainly use it.