I haven't, but would be interested to hear your thoughts once you have them in circuit. They're SMD parts as I understand it, so I'm assuming you're using a SOIC to PDIP adapter? The fact that Fig.1 in the datasheet is a Baxandall tone circuit should be an encouraging sign for EQ use though, I'd think.
One thing to watch in a lot of faster, ultra low distortion modern op amps is local decoupling of the power rails - if you're using the Audiox boards, they're laid out for NE5532s and the OPA1656 may (or may not) need a different arrangement. It'll be worth reading through the OPA datasheet a time or five to make sure you know whether you need to sneak any additional caps in there somewhere to stave off potential oscillation and instability. You might need an oscilloscope to tell how well it is behaving once in.
As ever, other, wiser heads than mine may be able to offer better advice!
I am building four of the W492s right now. Im am using the OPA1656 as opamp. Anyone used them before?
Michael