Have you seen
Ils yet?
There's
The Strangers, which was OK, but I think you mentioned seeing that one before...
There's also
Funny Games, though I'm not sure if it's really up your alley. Worth a try, though.
There's
Altered... Which is like a home invasion flick... with aliens. I know it sounds ridiculous, but it was actually pretty gory and intense. I was impressed with it.