Famo.us is most certainly suitable for landscape oriented Design. The sizing feature of 'undefined' for Famo.us surfaces and the origin constraints on modifiers allow for designs to fit any number of device sizes and orientations.
Detecting an orientation change using only Famo.us can be done using something similar to the following..
Engine.on('resize',function(){
size = context.getSize();
if (size[0] > size[1]) {
// landscape
} else {
// portrait
}
});