A contest is coming up in my area for soloists, requiring music for soloist with orchestral accompaniments. I'll be auditioning on a marimba, but am not yet sure of any good 4 mallet solos with accompaniment. Any suggestions? I'm just a student, so difficulty can't be to great (around the level of Mexican Dances, if anyone is familiar with that piece). I've seen composer names including D. J. Long, E. Hause, and E. Diemer. Any suggestions or advice would be greatly appreciated.

Try the Ney Rosauro "Concerto for Marimba." It's not too much more difficult than the Mexican Dances, I don't think...

I would agree with Zac.
The Ney Rosauro "Concerto for Marimba" would be a good choice.
The tempo of a the first and last movements can be tricky, however they do sound almost as good at slower tempos.
This is also a well recorded concerto so finding a good recording is easy. Check out Evelyn Glennie's CD "Rebounds"

Scott LeMieux
ThePercussionist.com