This isn't the first time we have had this conversation here. An actual mechanical shutter that reaches that speed would definitely be helpful. Or better yet, a global electronic shutter that goes faster than that would be even better.
To date, I've probably shot at least 8-10k images at 1/10000th and faster with my mirrorless rig. We haven't had very many rainy days here in California this year so we have had ample sunlight for a minimum of 8 hours everyday for a good while now. The type of sunlight that would require a faster shutter speed than 1/8000th at f1.2. I have been doing this with just an electronic shutter which causes problems depending on the type of movement in the scene. Either way, I have tons of shots captured above 1/16000th all the way up to 1/32000th.This has been one of the reasons I love this cam so much. Knowing that, I would love it even more if I were able to have those types of speeds on a mechanical shutter (or global electronic).
If I remember correctly, I posted samples in the other thread where this conversation was previously had.