[nullc]

I technically have 10 plus a 100GBE card in them, but due to nvidia chipset limitations using more than 9 in a single task is a pain. (Also, IIRC one of the slots is only 8x in my chassis)

Supermicro has made a couple 5U chassis that will take 10x double width cards and provide adequate power and cooling. SYS-521GE-TNRT is one such example (I'm not sure off the top of my head which mine are, they're not labeled on the chassis, but they may be that).

They pricey new but they show up on ebay for 1-2k. The last ones I bought I paid $1800, I think the earlier set I paid $1500/ea-- around the time that ethereum gpu mining ended ( I haven no clue why someone was using chassis like these for gpu mining, but I'm glad to have benefited! ).