How big of an area do you need to mow?
I used to have a pull behind like you're looking for (don't recall the brand) but for the areas I need a bush hog, I arrange it that a local farmer comes in to do it and he bales it (as part of a trade). I then keep an old garden tractor for touching up the sides and along the fences where he can't reach. Although it's a finish mower, it rips through everything. A mower/shredder that's a pull behind costs $1500-5000. An old garden tractor with good mower deck is cheap. I paid under $400 for an older Craftsman with a 2-cyl Kohler.