He is keeping it small for flying purposes. I think if it was me I would just go ahead and use an 18" crash ride and add a 12" tom to that setup. It wouldn't add that much to the footprint (in fact in the performance video it looks like he has an unused arm that could be used to mount a small tom) and I think I would rather have a crash ride over just a crash and a single tom gives a bit more versatility.
I actually have a kit that is configured 18" (kick), 8/10/12 toms and I have a 13" snare although a smaller one like he has in the video would be neat.