In Sony Vegas you can set the framerate to 100fps in the “Project Video Properties” menu, and you’re able to shift video and audio in increments of 1/100 of a second, instead of 1/25 of a second (with PAL)… That is not quite 1/48,000 of a second, but it gave me the extra accuracy I needed…
The video still plays back at 25fps, when I preview it.