I bought a grapple attachment from a guy on ebay that is working great. It's only 18 inches wide, but I'm doing a ton of work with it and have few complaints. I did have to beef up the front a little, but other than that, it worked great. Of course, I'm moving trees more than brush. I'll attach a few pictures so you can get an idea. Watch ebay and you can probably find him. If you can't, I may be able to find some contact info.
The grapple was around $400 or so, and then you have to run hydraulic lines, which isn't cheap. I think I spent close to $200 for all the lines and fittings I need to run to my rear SCV.