Mouse speed @ extreme wide resolution

[Bek]

As a possible way to get around the issue for now:

For my mouse at least (logitech g9) you can set the DPI for x and y axis separately. So you could increase the y ( I think y's horizontal?) dpi slider to get it close enough to what you need while leaving the x DPI down. With a range of 200 to 3200 (4000 on g9x) you should be able to get it playable.