Did you take a dremel to the backplate or to the screws? If the screw, I hope you cut it down far from the motherboard. Steel dust isn't what you want in a computer.
If you've hacked up the case enough that you can take the backplate off without removing the motherboard, good call. I've been meaning to get around to that for ages now.
On second thoughts, I'm not sure I'm using standoffs with an x58 board, the backplate is pressed up against the cpu bracket. That might be a mistake, but it's working well enough if so.