Upgrade path from 4x 3090s

Hey everyone, looking for some upgrade advice.

Right now, I’m running 4x 3090s hosting Qwen 3.6 27B 128K in full precision. It's a great model, but I'm looking for a step up and trying to figure out the best "middle-tier" hardware path.

I've seen people here mention running 8x 3090s (192GB VRAM total), but I'm not sure if there are actually better models that take advantage of that tier yet (maybe MiniMax M2.7 or DSv4 flash?). Correct me if I'm wrong but running DSv4 on Ampere will be a pain.

I also considered an RTX B5000 for around $4200 + tax, but the VRAM math doesn't seem to make sense. Buying another 4x 3090s is ~$4k for 96GB of VRAM, whereas the B5000 only gives 48GB.

I'd love to get some thoughts on a few things:

What setups are you running to host models better than Qwen 3.6 27B without dropping $10k+ on a B6000?

What models are you actually targeting with heavier setups?

Is building a 192GB rig worth it? More precisely - do model providers even target this VRAM tier for upcoming releases?

For context, I don't have a hardcore production use case. I code for a living, love tinkering, and just find building these rigs fun.

My current open frame has room for 4 more. If I do 8x 3090s, I’ll route power from two separate circuits and power limit each card to 220W. At 8x, the slowest link will be a PCIe 4.0 x8.