A Russian youtuber that goes by the name of VIK-on has modified a NVIDIA GeForce RTX 2070 to support 16GB of Memory. VIK-on was able to access leaked NVIDIA PCB diagrams for GeForce RTX 2080 SKU which outlined how to configure the board to support 16Gb memory modules.
The Graphics card was successfully recognised in GPU-Z. VIK-on tested the card in FurMark, however the card failed during the test. He was able to run a full 3DMark TimeSpy test and got a score of 6176 points but it was lower than a normal RTX 2070 score of 9107 points. You can check the full video below.