I have the same question. I was considering buying "SABRENT Rocket DDR5 128GB U-DIMM 4800MHz Memory Kit (4x32GB) for Desktops and PCs (SB-DR5U-32GX4)" from Amazon but it's not on the QVL (do they ever update this document?). There's no XMP but I can't get the XMP profile to be stable with my current 64gb setup anyway. Hopefully some brave soul has tried.
Decided to plunge in and take the risk to upgrade to 128GB DDR5 RAM.
What I did: Upgrade to the latest BIOS 2305. Purchased two Trident Z5 RGB (F5-5600J3636D32GX2-TZ5RK)
What happened: Unable to boot to 5600 Mhz. GSOD after a while if booted successfully into Windows 11.
How to recover: Clear BIOS, set to XMP 1, reduce speed to 4600 Mhz, Booted successfully and stable. Ran memtest and no error.
Outcome: Happy that I managed to have 128GB in my system and stable. Sad that it cannot run at 5600 Mhz. Was thinking maybe if it get the 6000 Mhz version, maybe I can hit 5600 Mhz. But with the high price, think might as well forget it - for now.