If you are on a tighter budget and want a good rear end I got a Stock Car Products 9" a couple of years ago through Jerry at Camburg. I put it in my 7 toyota after breaking two axles in a Lincoln rear end.
You can specify the width, brake calipers, hubs(aluminum or steel) and it's a full floater. I think you can only get them in 31 spline though so I wouldn't use it on a full size, just a Toyota or Ranger or something like that. Or maybe a full size if it doesn't have a big motor.