I've never liked the awkward, wrist-wrenching placement of the MBP trackpad 'below' the keyboard, between the keyboard and the person using the MacBook.
I'd like to stick my magic trackpad over either the right or left speaker ( we're talking 17" MBP here), iether being far more ergonometric and natural tackpad locations than the Apple-ordained position.
Because the trackpad battery case, I'd like to hang that over the right (optical disc slot) or left (magsafe and other ports) side of the MBP.
So the magic trackpad would be either -90 +/- rotated if it's battery case hangs out to the left, or +90 +/- rotated if its battery case hangs to the right, relative to the built-in trackpad.
I don't see a setting that would maintain XY tracking consistent with the built in trackpad, for the same locator motions done instead on a magic trackpad rotated either -90 or +90 degrees relative to the built-in trackpad. If thise is this option, this isn't an RFE, merely user training.
Also, to ward off CTS, I frequently switch my locators ( magic mouse, trackpad, logitech trackball, 3Dconnexion 6DOF spacemouse and Bamboo tablet) between the left and right side frequently, and use some on the left side and others on the right side, and change them up frequently, so it would be really nice to have a way to quickly toggle 'toggle' between -90 portrait, landscape, and _90 portrait orientation settings.
Even with a supplemental magic trackpad, it's convenient (or necessary, for some CAD tools) to use other locator devices simultaneously, so whatever settings are applied to the magic trackpad shouldn't affect e.g. the built-in trackpad on the MBP.