Apple does not sell a 64GB variant of the M4 Mac Mini. IIRC they never have; its always capped out at 48GB.

If you were planning on getting an M5 128GB; just get a DGX Spark (~$4500) or a 5090-equipped machine (~$4500) plus a Macbook Air (~$1500). You'll come in below the M5 Max 128 pricing (~$6700+ USD) and be happier for it.

That's incorrect, I have one on my desk right now. They've stopped selling it now, but I got one a year and a half ago:

> Apple M4 Pro chip with 14‑core CPU, 20‑core GPU, 16-core Neural Engine 64GB unified memory 2TB SSD storage 10 Gigabit Ethernet Three Thunderbolt 5 ports, HDMI port, two USB‑C ports, headphone jack Accessory Kit $2,649.00

The Mac mini was available with 64GB of RAM literally 4 days ago; the option was discontinued on June 25th.