Flash OFF

I know, if I don't pop up the flash, it won't fire, but is there a setting where you can tell the camera to keep the flash off and bump the ISO/slow the shutter.

The Flash button brings only AUTO flash and other modes

You could use Av or Sv mode and raise the iso yourself, or Tav mode and let the camera raise the iso as much as is needed? As you say with the flash not popped up, it's always off.

I'm a bit confused like you said, if the flash isn't pop-up it won't use the flash and neither use it for metering.
You may get a warning that the camera wants to use the flash but if you don't pop-up it it will meter like normally.
So there is no need for an off setting.

When the flash is down the flash is off.

Ok that's what I really wanted to know. The metering bit when flash is not popped up.