tinybox green v2 with 4x RTX Pro 6000 Blackwell

If people really want it, we'll build it. Everything the same as tinybox green v2, except:

* 4x RTX Pro 6000 Blackwell
* No 5090s
* 384 GB VRAM (vs 128 GB)
* $50,000 (vs $25,000)

Made to order, 2-8 weeks to ship.