Is this for you to make something that will go back to the school, perhaps for a fundraiser? or was it just a gift to you, to do as you wish and then have it for yourself?
Marching Band uniforms can vary so much ... so could you show us a pic of the uniform?
I think that would really help to generate ideas as to what might be do-able.
There could be some really neat things that could be made.
What kind of material is it?