Limit or change Scheme Destinations in Xcode 4?

Updated Answer

Hmmm. This works for me with ONE target. I removed the platforms from the Supported Platforms in the configuration and they disappeared from the Scheme.

I then tried adding another configuration that allows the simulator and it's still just the device destination visible. Then I duplicated the target and added in iphonesimulator ... and the simulator shows up in the scheme for both targets.

Unfortunately, I think the available destinations are an aggregated list of those available to all targets. File a bug report: http://bugreporter.apple.com

Another Update

AH! It looks like an Xcode bug with updating the Scheme selector! I configured each target's settings - one to omit the simulator and the other to keep it - then closed and re-opened the project. Magically, the first target had only the iOS Device destination while the other target had the device + simulator destinations.

So, the answer may well be to duplicate your desired targets and set them to allow only the device, then make sure your scheme is properly named so you know which target is being built. Close and re-open the project and the list should show up just as you'd expect.