That is very good news ! ^^
Maybe a “difference” intensity style would be great, because that would give us directly in one shot the specularity !
About HDR, I am currently doing some tests with JPG+EXIF (exposure time+aperture+iso converted to EV values then applied to the pixel value) to .EXR Half float images (with more than 30 EV of dynamics), and this is promising ! My idea is to then texture in HDR (Float16) and use a shader at runtime to do the tonemapping.