Jeff, Images in the equirectangular projection can be created with any aspect ratio you like. You need to specify a full coverage of 360x180 degrees, which will give you a 2:1 aspect ratio. This can be done in a variety of ways: From the Panorama Editor Projection menu, select
Spherical: 360x180 equirectangular, or use the sliders on the Panorama Editor window to adjust the horizontal and vertical angles of view to
360x180, or set the width and height on the Create Panorama tab to pixel values exactly in the ratio 2:1, or set 360 and 180 values on the Panorama Settings tab (in Advanced mode).
John