I contacted ASRock recently as I am also waiting for the Extreme7 Gen3 to release and they told me it will be on newegg.com this week, so I am checking it daily, but I am sure that it will be pricey.
This might sound like a stupid question but can I just plug my 2 displays straight into the motherboard and it will recognise the 2 monitors, so I can set different screen resolution?
This depends on the motherboard really. The i5 does have built in video and the Z68 series supports it. I believe all the Z68 motherboards that have the dual monitor connections do support two monitors. Do you know what resolutions you will be running on your monitors? I don't know if any certain resolutions are required for your work but the integrated graphics will probably be limited as to the resolutions it can push out efficiently.
Also, just a thought, but for the audio work you are doing would hyper-threading benefit you? The reason I ask is because the i5 does not support it, but the i7 does.