Since 2011 and many devices are having GPU and WiFi chips capable of WiFi-direct and miracast, and still android-x86 doesn't implement it yet. If you check wpa_supplicant, it does add support for both wifi direct and wifi display, renamed as P2P support. And there has been two projects that really got my attention that use Wifi direct :
Having Wifi Direct and sinking/casting implemented on Android-x86 would be totally amazing, buying those cheap Atom Boxes (or pentium/celeron) would do so much good by having them plugged to a normal TV and making them a powerful multimedia server with Miracast capabilities. For others (like me) having And-x86 on my Tablet would be also awesome to cast my screen as I do on windows on external TVs.
I know it isn't easy, but I think it's totally doable. Most used Wifi cards like Intel 6235 Advanced-N, AR5B195 (and AR5B95 - no BT version) and most ath9k cards support P2P, Intel 7000+ series do too, Intel 6000+ have some selected devices that support that, for realtek, ralink/mediatek and others, the latest devices do support it, but I do not have any information.
Thank you.