hi man,
i was struggling with the same exact problem your having for 2 days. fortunately i have the same build as you do except for the graphics card which i don't think that the problem has to do with anyways.
i did everything you did, removed hdds, usb sticks, tried to delete some kexts and change bootflags etc with no luck....what resolved the problem for me was to "rebuild caches" and "repair permissions" using kext wizard AFTER installing the following with multibeast:
-ddst free
-3d party sata
-trim enabler
-usb 3.0
-evoboot
-fakesmc (not the plugins)
-nullcpupowermanagement
-voodootsync 6 cores
i didn't install any audio drivers as i have a firewire audio device. also my network card seems to work out of the box so i didn't install any network drivers.
in extra/org.chameleon.plist i added: kext-dev-mode=1 npci=0x2000 under kernel flags.
after your done installing multibeast stuff and modifying the org.chameleon.plist, download kext wizard 3.7.1.1 and open it, select your hard drive and rebuild caches+repair permissions. restart and your good to go.
this is what worked for me i restarted 6 times to make sure that it wasn't a coincidence
hope this helps you out
cheers