SGuru, Z-Sys, Junger, TC Electronic and Waves are a few of the pro audio makers of digital EQ products. Mastering engineers are very particular about their equipment and I believe the majority of them still use analog EQ (even for all digital projects). It may have to do more with their level of comfort than ultimate sound quality. Regarding DSP processing, to be convincing the emulation would have to go beyond matching frequency response curves and get into areas of dynamic distortion behavoir. Imagine flipping a switch to dial in a KT88 sound versus a 300B. With sufficient DSP power (and its getting cheaper everyday) and skillful software, it should be possible.
Digital Modeling of Sonic Signatures
A company called Line 6 has a number of products aimed at electric guitarists. Basically, they are digital, solid state signal processors and/or amps that use DSP to sonically model the sound of specific guitar amplifiers. The sound palette ranges from classic Fenders, stacked Marshalls, clean Rolands and more modern hi-gain, class A designs (Mesa-Boogie). Amazingly, the digital recreations are very accurate. I'm not saying they're indistinguishable from the originals, but the recreations are real close. My question is -- why are no audio manufacturers applying similar technology to recreate, or mimic the sonic signature's of well known high end amps and preamps? I'm imagining an outboard processor that the user could dial in any sound palette they desired, whenever they desired. Would any of you buy a product like this?