93 skaters. 10 minutes. 5 hot shoe flashes. 5 stitched shots.
The full-sized version of this photo was stitched from 5 frames. It's 39MP, 13,830px wide. Naturally, I had to ask the skaters to stand very still while making the frames, and because it was an experiment which I didn't have high hopes for, I only took one set of five. That set turned into the final version (100% crop below).
All shots 1/13sec, ISO400, f/4.0. Straight away, you can probably see one of the problems. The 1/13sec shutter speed required for the ambient/flash balance meant that there was some blur. I didn't use a tripod, but I did brace the camera directly atop the ladder I was standing on. Turns out ladders are pretty flimsy when they have 260lb of photographer on them.
The flashes were 3x 600EX-RTs, and 2x 430EX IIs. Output was roughly balanced by setting the 430EXIIs were at full power, and the 600EX-RTs at 1/2 power +0.7 stops. They were placed on a light stand apiece, spread evenly in front of the subjects with their built-in diffusers down, gelled full CTO, and the exposure was adjusted by moving the stands back and forth. All were triggered by PocketWizards.
I did quite a bit of pre-planning for this shoot, mainly because I didn't want to waste much time with that many people waiting, and I'd agree not to disrupt practice for more than ten minutes. I was asked a few hours before starting if I could do it in 3 minutes (internal response: #$&% no, external response more measured). The league was in front of the camera for about eight and a half.
I'm pretty pleased with the results considering the restrictions, and if anyone else finds themselves in a similar situation, I hope this overview is helpful. Keen to hear everyone's thoughts on the process, including critique, and I'll happily answer anyone's questions.