Actually, the Targus wireless keyboard has a built-in mouse-type navigation device. It's not a true mouse, nor a touchpad. It's more like the "joystick" type mouse that used to be found on many Toshiba laptops. I've attached a picture of it from their website....
Here is a link to the product website:
Click Here
Here is a link to it for $55.79 at Amazon:
Click Here
I'm not positive if it works with the X3/X3i or not, but I would imagine that it should work fine. Their website shows that it works fine with the X5 running WM2003, but their compatibility list hasn't been updated since the X3/X3i have been released. There's no reason that it shouldn't work though, since Targus obviously has WM2003 drivers available.