We've got 2 customers who use a drum cutter that mounts on a skid steer. The attachment that you provided a link to, is a tree cutting bush hog. The drum cutters are 3-4 times faster and do a much better job at mulching the material. You could hire someone with the drum cutter like I'm talking about and they'd be cheaper than you renting a machine and doing it yourself just from difference in speed. If one of them comes by in the next few days I'll ask them what their hourly rate is. I think it's $150 an hour but I may be wrong. I know one of them has told me how much land they can clear in an hour, if the trees are fairly small and I was amazed at how much they could do in an hours time. I don't remember how much land per hour, but I know it was more than 1 acre per hour.