good question. the per hour is removal , hauling, and dumping...so it will be kinda high sounding but nothing less than 100/hour..or even better yet...charge a flat fee, this is the easiest. when ya bid, keep in mind the biggest problem is gonna be hauling the brush away. you can rip out 30+ bushes in 2 hours but you have 6 trips to the dump.
removing old stuff really isn't that bad until you hit yews, burning bush, trees, or honeysuckle to name a few biggies.
most things even huge things can be handled with elbow' grease and a full metal spade--very sharp. you would be amazed at how easy things come out when you know what to look for.
BUT, big old yews go either amazingly easy or the worst thing that could happen to ya. the "bobcat" and forks works very well. i don't recommend a winch just because it WILL pull the truck, leave skid marks or tear turf. the key to making money is to make as little mess as possible.