That is absolute cake for any 3-axis mill. Face and square a block, put it in a vice with soft jaws, let a ball mill go to town with whatever stepover / scallop height is required to meet your surface roughness desires. If you were really wanting to limit tool changes, or if you don't have an ATC, you could do it all with a ball mill, including side-milling the edges. If you hold the workpiece in jaws that are only 2-3 inches wide, on the flats, you could clear the ends enough to get the radii on the corners.
If you wanted some weight-reduction, or a pocket to include some electronics, you could mill that into the bottom side before flipping it over to do the contouring on top. Easy part.
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NX8.0, Solidworks 2014, AutoCAD, Enovia V5