i like the idea, use what ya got for another purpose, or make a tool of a tool. probly alot cheaper than buying a quality impact and a hammerhead type impact seperatly.
never seen one before today though. i just remember the manual ones with like four different rods that moved back and forth to turn the drives.
or not. thats a little pricey for me.
... I'd spring for a Hammerhead if I was in need of such an impact wrench configuration. If it's a one time need then I'd probably just weld something up to get the job done.