A PlayStation 2 dev kit (with 128 MiB of RAM instead of the standard 32 MiB).
Between the VUs, the R5900's SIMD (MMI), the GS and the I/O buses (FireWire, Ethernet, IDE, Memory Cards...) to stream model weights, the smallest Bonsai models (or aggressively quantized Qwen3.5-0.8B) and some really cursed programming might just eke out something the PlayStation 2 has no business running.