Ok, the video scaler queue change is now live: SD and low-resolution video output runs on a new, high-priority queue, with HD video output and transcodes of files over 15 minutes in length run on the old queue.
Note that existing queued conversions will continue to run on the low-priority queue until it runs out, but most new uploads from here out will have web-ready output much faster.
(Load on the servers may be unbalanced for a bit, and may require further tweaking to best balance responsiveness and throughput, so we'll keep an eye on the graphs.)