There have been a few different AIO setups over the years that used copper rads, but they don't really perform enough better to justify the much higher cost. AFAIK the only things you can still buy are the Alphacool Eisbaer. You could also build your own with either a rad/pump combo with a normal CPU block. Or a CPU block/pump combo with a normal copper rad.
CPU AIO
SHOP.ALPHACOOL.COM
Komplettwasserkühlung für AMD- und Intel-Prozessoren mit Kupferradiatoren und Schnellverschlüssen, geeignet für alle CPU-Sockel.
Granzon 30mm Radiator-Pump Combo for Build-Your-Own AIO Systems — Available in 120 mm fan size in four lengths (GZMN)
WWW.PRIMOCHILL.COM
This Granzon Radiator-Pump Combo for Build-Your-Own AIO Systems (GZMN) integrates a high-capacity radiators with a compact PWM-controlled pump for streamlined custom AIO setups. Designed to be...
Barrow CPU Block-Pump Combo, 17W PWM/10W Intelligent AIO Block-Pump Three In One 5v A-RGB OLED Screen Metal Cooling Cover, LTPRK-04I FBLTPRK-04I LTPRKA-04 FBLTPRKA-04 LTPRK-04I M LTPRPA-04 M LTPRP-04IS LTPRPA-04 | GPU Waterblock – Gaming & AI Server Liquid Cooling | FormulaMod
WWW.FORMULAMOD.COM
Buy Barrow CPU Block-Pump Combo, 17W PWM/10W Intelligent AIO Block-Pump Three In One 5v A-RGB OLED Screen Metal Cooling Cover, LTPRK-04I FBLTPRK-04I LTPRKA-04 FBLTPRKA-04 LTPRK-04I M...
Amazon.com
WWW.AMAZON.COM
Realistically, you just just save your money and buy the Arctic unless you plan to expand it and cool a GPU as well.