Speaking of mulch and soft landings it recently came to my attention that my ten year old has never been on a merry go round. They do not exist as playground equipment anymore. Time to fire up the welder?
Can't remember for sure, but I think there's still one in the park here. I know Comanche still has at least one.
A cheap wheel hub, or better yet a cheap cargo trailer axle from the scrap yard makes an excellent center bearing. It'll handle a heck of a lot of load, and you can simply set the axle in concrete for your base. Cut the axle in half and you've got two. Then use a rim that fits for the center of your merry go round top, and you can easily remove the top for mowing or maintenance. Could even make multiple interchangeable tops with a set of rims.