So yeah, the beefy Radeon RX 6900 XTX (most unlocked GPU) was spotted and photographed, as an engineering sample even. Spotted on Weibo, a Chinese social website, a user has posted photos of what seems to be an engineering sample of AMD's Radeon RX 6900 XTX graphics card. 

The ES sample has been paired with an all-in-one liquid cooler based on a 120 mm radiator. The Navi 21 XTXH GPU version is the more unlocked and further binned GPU with higher wattage allowance, some are making their way through LCS cooled AIB cards like PowerColor RX 6900 XT Liquid Devil Ultimate, ASRock RX 6900 XT OC Formula, and Sapphire RX 6900 XT Toxic Extreme graphics cards. 

Apparently, a reference design was developed as that is what you're looking at, though we doubt it'll be released. There's no point for AMD to spend marketing budget on it as anything sells fast anyway. Well, at least we have photos to sink our teeth in. 

AMD Radeon RX 6900 XTX Engineering Sample Photos