Bobcat makes a mower to fit quick attatch and is operated by a hydraulic motor, and you can get either a 72" or a 90", depending on how wide you want to cut. Several manufacturers make brush cut mowers of various sizes and types that are hydraulically driven. I have a 90" three bladed finish mower I have been using to cut 56 acres for the last three mowing seasions on my Bobcat Toolcat. Mowing out in front and being able to see what you are about to "accidentally" run over is great. My wife, however, says now I have no excuses for cutting up stuff she plants in what I think is a stupid place!
Warning, expect severe sticker shock!