In this video, one of my favorite percussionists, Evelyn Glennie, demonstrates her stunning virtuosity playing Ney Rosauro's Marimba Concerto I.
Unfortunately, about halfway into the third movement, the video ends abruptly. However, I found another video (below), with Samuel Peruzzolo on marimba, that has just the third and fourth movements. I'm glad I stumbled upon this one because it is kind of interesting to hear it with only piano accompaniment instead of an orchestra. (The pianist is Liziane Venes.)
And finally, you can see the composer himself playing his concerto with an all-percussion group at Vic Firth's web site. Very, very cool!