https://www.tomshardware.com/pc-components/gpus/chinese-work...
There's also unreleased Nvidia engineering samples of cards with doubled VRAM like this - https://www.reddit.com/r/nvidia/comments/1rczghu/update_unre...
There are some on sale via eBay right now. The memory controllers on some Nvidia gpus support well beyond the 16-24gb they shipped with as standard, and enterprising folks in China desolder the original memory chips and fit higher capacity ones.