I have my 60" tv mounted on a tv mounted to the wall per the instructions. However, I do not get enough swivel before the edge of the tv hits the wall. So I want to attach two 4x4's from the ground up to about 6 inches higher than the top of the mount. My plan is to attach the 4x4's to the studs in the wall and then attach the mount to the 4x4's. And if I still need a little more space from the wall, I was going to use 2x6 across the two 4x4's and attach the mount to the 2x6's. My guess would be that if the 4x4's are attached top, middle and bottom to the stud and with the 4x4's touching the floor, there should be no problem???
That'd work. there are easier ways though.
If your TV mount is already mounted to studs you could just pack your 4" or 6" of wood behind it and screw that wood to the studs then screw the mount to the wood. there's no need to have the wood extend all the way down to the floor.
I'd use 2x4s drilled half-way through with a spade bit and then screwed through the bottom of the holes to the studs with 4" chip-board or drywall screws
All that wood will weigh more than your TV. I like @Kris comment about the 2x4's. Stack two on each side, they don't need to go to the ground, just the height of the TV. Drill through them with a 5/16 or 3/8" drill and use 5" lag bolts with washers into the studs. Make sure you hit the center of the studs. you can then add your 1x4's for additional distance if needed. Good luck.