I searched a while I didn't find any existing model or project to mount a BlueSCSI v2 into a NuBus slot, so I knocked one together. This is a rather niche thing that may or may not be useful to anyone. In fact, I myself will probably not use it since I'm pretty happy with the SCSI2SD in my Quadra 650. But I thought this might be nice for anyone who, like me, doesn't have a hard drive sled, let alone the drive chassis to which it attaches.
I have posted this abomination on GitHub: https://github.com/jimfrob/BlueSCSI-v2-NuBus-Mount/tree/main

Nice work! Do you have a photo of it installed you can share? Just having trouble visualizing how it all fits together.

I hadn't even printed the mount because I don't have a spare BlueSCSI. But I'm printing it now, and I'll even print a facsimile of a BlueSCSI so that one might see how it all fits together. I have an awful lot of filament in a color that turned out to be not so great of a match for the projects I wanted it for, so this is an excuse to use it up. I should be able to provide pictures of the assembly this evening.

Here's the rough mock-up using a 3D printed facsimile of the BlueSCSI PCB. I'll be able to get a picture of a test fitment in the Quadra this evening.

Looks like Google AI let me down yet again. It told me I should use the Macintosh II-family connector shields for this project. While the model I made should work with a Macintosh II, it does not work with the Quadra 650 because the NuBus expansion ports are of a different design. I'll have to have a complete rethink and redesign. Anybody else notice that Google knows absolutely nothing about the physical characteristics of vintage Macs?

I have a IIci with a Radius Rocket in the NuBus slot nearest the case, nothing in the center NuBus slot, and a Radius Thunder 24/GT graphics card in the innermost NuBus slot. I'm hoping to order one of the SCSI Booster clones by @max1zzz , and it would be neat if there was a NuBus slot mount for BlueSCSI that would work with the IIci, so I'm keeping my eye on this thread.

Just so everyone knows, I haven't given up on this. I have a rough prototype of the mount itself, but I haven't gotten to the bit that holds it in place yet as I've been focusing on recreating the bezel for the AppleCD 600E. I expect to have that model finalized shortly. When it is, I'll make a post in the relevant section here along with a link to the STL.

I have 2 overlapped Nubus slots (DOS card) in Q950, and if I manage to use at least 1 of it, it would be great.
I'm keeping my eye on this thread too. [eyes]

I'm satisfied with the alignment and stability using my mock-up in the Quadra 650. This design simply modifies the available models for the NuBus slot cover to remove the clips, add an SD card opening, and add a bit of length to fuse with the universal BlueSCSI v2 mount. This is then attached with an M3 bolt to a piece that fits snugly over the NuBus connector. I can't be 100% sure of the alignment of the SD card opening as I'm only able to use the 3D-printed mockup of the BlueSCSI v2 PCB. I've joined the waitlist for a BlueSCSI kit from Joe's Computer Museum, so it'll be a while before I can test it myself. In the mean time, anyone who has one already and wants to test it out can download and print the models. I'll have them on GitHub shortly.

There's a fair chance this thread needs to be moved to the 3D Printing forum like my AppleCD 600E bezel. I haven't figured out how to do that (if I'm even able to do so myself).

I decided to play musical hard drives and move the BlueSCSI from my SE/30 to the Quadra 650. The mount I designed works pretty well, though I probably should have made the SD card opening just a bit bigger. The important thing is that it works.

As far as I understand, the Q650 and Q950 cases are not much different.
I printed it out and tried it on my Q950 -- it doesn't fit.
I'll try to make the frame not much thinner so that it can move deeper, beyond the petals. In this case, it should be better.

Though it's a touch tricky, this is designed to be levered through the NuBus slot opening and then pulled flush with the outside of the opening. It looks like you were just trying to butt it up against the inside of the opening. If you lever it through and then pull it back snug, the bit that goes over the NuBus connector should hold it relatively tightly in place. I have it in place in my Q650 now with a real BlueSCSI, and it works beautifully.

@jimfrob Yes, exactly, you're right. If you put it at an angle, everything works out.

I still have to order BlueSCSIv2 to finally connect it to ATTO ExpressSilicon IV.