Yes, but I haven't run out of storage down below yet. It would have to be for infrequently used and light weight items. Northwoods Manufacturing puts cargo racks on the roof of most of their trailers. It's a good use of space.
Just seems like a logical storage option for those seldom-used items.... Would free up basement storage for those items you would want to be able to get to easier.... As long as its height is more than the AC units, it should be great....