I want to be able to record a person with headphones on, then hit a button or click something and switch the sound to the monitors to listen to it, then click/push button again and all the sound goes back to the headphones for recording again...
If you allready have a decent soundcard, any small footprint mixer will do this. You just use a pre fader send to send to the headphones. Unless you can use the same mix in the can's, as you route to the monitors then the headphone socket in every mixer will do the trick. I'm assuming you allready have a mixer of some kind with micpre's, for that "person".