Outboard EQ that covers more than the bass is very difficult to do - some folks build their own systems using some pro equalizers, computer software, and a microphone, but systems like that require you to have separate amplification because the EQ has to be inserted between the receiver and the amplifiers. The only outboard systems I'm aware of that are complete "turn-key" packages (all the hardware and software that you need) are limited to the subwoofer because everybody's subwoofer amplification is outboard (either a standalone amp or an amp in the sub itself).

EQ systems like this are probably going to become common in receivers and processors, but there are some serious issues to keep in mind when using them. For one thing, EQ's can only correct for the spot in the room where the microphone is located, which means that anyone not sitting in that spot could end up worse off with the EQ than without it. (This is why some of the more expensive auto-EQ's use multiple microphones, which lessens the danger of this but doesn't necessarily eliminate it.) For another thing, many people like the sound of their speakers - and that sound may be due in part to a frequency response that is not ruler flat from 80Hz to 20,000Hz. An EQ system will try to adjust to acheive that flat response, which can impact the sound produced by the speakers in a way that you may not like. Lastly, while the really good EQ solutions are generally regarded as very beneficial, EQ'ing (either automatically with a less-than-stellar software logic or manually) can do more harm than good in many spaces. That's why you'll find so many people recommending that you start with acoustic treatment and speaker placement changes before attempting any EQ.

I don't say all of that to suggest that EQ is inherently evil. EQ can be a useful tool if used properly, and in a few more years we'll probably find that nearly all new receivers and surround processors offer some sort of automatic and/or manual EQ capability. It's just important not to mistakenly assume EQ to be a magical cure for acoustical ills.