So, I decided to play around with Mini vMac and A/UX, but I couldn't get the ISO to be detected upon boot from the disk image. Decided to go with Basilisk II, and I've gotten this far for now. Everything I've seen online says it won't run on Basilisk II, but is this as far as they get? If not, then I'd say it's some progress. 

I assume I need to create the partitions for A/UX to work on the "Mac II" disk image.

@claudiom How did you do that? A/UX requires a clean rom and an FPU.

@praetor I grabbed some ROMs and configured Basilisk II with a "68020 w/ FPU"

See the pic...

@claudiom That's probably why you've gotten so far. Patched rom, and I didn't know Basillisk had an FPU now.

@praetor OK, so the stopper now is that I can't modify the contents of a disk image using Apple HDSC Setup or Drive Setup, and there's no way that I know of to modify the disk image and create partitions inside of it.

Unless..... Gparted? 

@claudiom that's bizzare. Basillisk has a tried and true SCSI emulation stack, so not sure why the image would be read-only. 777 the image and see what that does.
@praetor Well, I don't think it's a permissions thing more so as it's a thing that neither of those drive setup tools can detect. It's in a subdirectory in my home directory, so the permissions shouldn't be an issue as I'm the owner.
@claudiom yeah. IDK. I use qemu for that sort of stuff. Unless it's detecting a disparity between how big the disk is being detected and how much data is actually on it. Kinda like how qcow will say a disk is 10G, but on the filesystem it's not that big. So maybe try dd'ing a raw disk image from /dev/zero and try?
@praetor Yeah, QEMU would have to be the final route for this, but I'm just tinkering around until I can get time to work on the actual Quadra 650 at home with A/UX. That will have to be repartitioned as covered here: https://aux-penelope.com/aux_3.0.htm
@claudiom if you can get it to work, that's a huge feather in your cap. Everyone will want to lay you. A/UX is known for being very persnickative. Even more so that OSX. So good luck!
@praetor Thanks! I re-read your last toot and it could be the disk image size that's the problem. I may just create a new one at 2 GB or so, see what happens there, and keep you posted. 
@claudiom yeah. actually create a raw disk image with zeros written on it, so there is actual data it can detect.
@claudiom oh also mind the blocksize. It may be like SunOS that needs a certain blocksize configuration.