what are some good marimba concertos with symphonic band or wind ensemble that an advanced high school percussionist could possibly play? I know this is a marimba forum, but if you know of other concertos (like for timpani or multi-perc) that you can recommend, that would be great.

I'm a senior in high school and next semester, I'm playing the first movement of Paul Creston's Concertino for Marimba and Orchestra (which has also been arranged for wind ensemble) with our symphonic band. It's 2 mallets and challenging, but not extremely difficult. It's a good piece to learn and have in your repertoire, even if you don't end up performing it. There are plenty more concerti out there and I'm sure that others will have more input on this topic. Hope I helped.

-Eric