Are you sure you can just integrate a new shader for HDR?

I thought the meaning of HDR is to have a higher range and precision. So when you have a bigger color or light depth, doesn't it mean, that also some engine commands dealing with bitmaps should support the same data width?

I mean, even the tools should be able to read hdr images then. So we could light a scene via a hdr background image as an example. So sky cubes could be an example for that. The lightmapper also should be able to read and write it.