Inspired by Paul's ISO 3200 shots of his two dogs here:
..I dug out this shot from earlier this year taken at Focus on Imaging:
..This is from a camera JPEG (not RAW, which would have been better), about 50% cropped, and at ISO 12,800.
There is some fine detail lost, but details that are prominent enough, like the text on the badge and the girl's eye-lashes, are very well preserved.
Who needs flash?