I don't know where else to turn.
There's basically some Touhou vocal compilation series out there. The titles are in Japanese so I can't just search it, and digging deep into YouTube isn't yielding any result. If memory serves, the video format is similar to what I drew up in pic related. There are about 20ish of these videos out there, but I just need to find one of them.
What do you mean by vocal compilation?
Is it from the official games, or is it fan-made material?
If it is the latter, I'd try searching by some of the popular circles that make Touhou remix music, such as ShibayanRecords, IOSYS, etc.
I don't recall seeing any videos with your specific format, sorry.
I should add that I know for a fact that some of them are removed from YouTube/NicoNico (for copyright conflicts?), so there's a possibility that they've all gotten removed. I usually use a niconico proxy to watch them (especially my favorite one), so it's just a matter of finding one of them. I have one of the urls saved on a broken computer, so if push comes to shove then I guess I'll salvage it from there at some point.