I can tell you for certain that it won't work for PowerPC. The PowerPC systems that NT was built for had either an ARC firmware or OpenFirmware. If you had OpenFirmware, you would just start veneer.exe. However, if your system booted in big-endian mode, the veneer binary would set little? to true and reboot. Unfortunately QEMU doesn't boot with either firmware options (hackware, openbios, ofw or slof) in Little? mode and it is a prerequisite for Windows NT. Interestingly, PowerMacs boot in little? mode but don't have a working display (I've tried MDD and QuadG5).
Let's talk about the firmware:
SLOF should be able to load the bootloader as it works in the PrepHV fork of qemu.
OFW should also be able to load it if it includes the following: ISO9660, FAT32, MS-COFF and MBR.
OpenBios is the furthest away, but since it's written in C, you could port the veneer ARC emulation directly in it as a symbol (you know where to get the NT sources).
I haven't looked at hackware.
You would need a: qemu-system-ppc -M 40p -vga cirrus (not enabled by default for PPC) and some hacking to do that, but not an insane amount. Build OFW build for little-endian working with fatfs, iso9660, mbr and the non-existing MS-COFF implementation.
read more:
http://tyom.blogspot.ro/2014/09/open-fi ... -prep.html - you have my HAL options analysis in a comment over there as well as a detailed firmware requirements.