This isn't possible.
You might be able to do some weird stuff, if the camera is parented to a pivot. Then rotate the camera slightly up compared to the pivot, and scale the pivot on the y-axis. That would do a non-uniform squash of the perspective, but it would also mess up the sense of depth...
The easiest would just be to make a second camera, that shows all the icons, and then adjust the viewports of the individual cameras. Although that's not what you want :)
You might be able to do some weird stuff, if the camera is parented to a pivot. Then rotate the camera slightly up compared to the pivot, and scale the pivot on the y-axis. That would do a non-uniform squash of the perspective, but it would also mess up the sense of depth...
The easiest would just be to make a second camera, that shows all the icons, and then adjust the viewports of the individual cameras. Although that's not what you want :)