So I was able to install Mavericks using Unibeast. I had to use a few boot flags to get into the installer (GraphicsEnabler=Yes, PCIRootUID=0, maxmem=2048, -v, -x, npci=0x2000).
However, I can't boot into Mavericks now, even using the same flags above along with others (IGPEnabler=No...