Altona has released Tilt&Shelf, a minimum-phase equalizer with continuously-variable slope and maximally-flat group delay. It's available for Mac OS X and Windows in Audio Unit and VST plug-in formats.
Tilt&Shelf was designed to allow tilt responses with a variable slope across the entire frequency spectrum. Two controls allow the slope to be freely adjusted from -12dB/oct to +12dB/oct. In addition, the same two controls can be used to add low/high-frequency shelves at any gain from -20dB to +20dB.
Tilt&Shelf was designed specifically to have a maximally-flat group delay, resulting in minimal pulse distortion. In addition, the group delay is maximally flat at any equalizer setting, independent of gain, frequency and slope.
Price: $39.