Well, I've dremeled my case, but only functional cuts (the intake fan slot was poorly perforated), nothing to show off with. I found the Dremel cutting disc frustratingly inadequate, but I've worked with angle grinders in a shipyard, so that's hardly surprising. If you're patient, you'll have no problems cutting the hole.
WEAR GOGGLES. I can't stress that enough. Rest your hand on something, the dremel cutting disc shatters on the slightest off-axis motion.
Time flies like an arrow, fruit flies like a banana. (Groucho Marx)