This has been something I too have been chewing on.
I was think more along the line of a scoop contraption that you could haul to location of brush, mulch etc., set down on ground on one side of pile, move tractor to other side of pile and either use FEL to load the contraption or use the box blade to push whatever in it. ???
When it was loaded go back pick it up and go dump. All without getting off tractor of course.
But of course you have to have someway to secure / tie-down the contraption to keep it from falling off when you dump. So I guess one time down off the tractor is not too bad.
Not sure how it will work with FEL, might need forks to work best.
I think I have seen something like this on commercial construction sites, using a "Lull" to move it around. But nothing with an open "front".
I'll let you know when I get my prototype built.