You can do it with MadMapper, until you get a computer powerful enough for playing back this 15'000 X 2000 pixels movie. I can playback a HAP movie of 10000x5000 on a decent machine so I suppose movie decoding will not be an issue, depending on your desired FPS and video quality (HapQ is higher quality than Hap, I don't think it would make things much slower anyway)
The complicated part might be:
- Getting 24 outputs from one computer... You can use two good gpus with 4 outputs and 6 Datapath fx4 or other 4k => 4x 1080p splitters. The memory has to be transferred from one GPU to another. I think this is doable. I did 19 1080p at 60 FPS a few years ago with an nVidia 1080 and another old card (AMD), with 4 datapath (4x4=16 streams) + the other outputs of my second GPU:
https://www.youtube.com/watch?v=jwUdfu5LsiU
- Setup up the soft-edge with all those projectors ! I can imagine it takes time. There are automated systems for that, where you place a camera at the center and it does everything for you. But it's quite expansive.