Both ideas sound great! This would be for all the children to enjoy so we are leaning toward something for the play area. The 5th grade area is basically an empty field)-:
Try Peaceful Playgrounds, they have a variety of things for a variety of prices and you can apply for grants. They are located at www.peacefulplaygrounds.com
How about a bench, picnic tables or trees for the campus. You could start a scholarship fund and when those kids graduate high school they would be eligible for the money to go to college. We are trying to start a tradition to have the PTO fund a 5th grade graduation field trip since the parents have supported the school for 6 years. We thought it would be nice to give back to the kids and parents who supported the fundraisers and events the school has had over all the years they have attended school. best of luck.