No, you can't make a single composition with a width or height greater than 30,000 pixels.
Your description leads me to think that this is a message that runs around an indoor arena on a very long and narrow digital scoreboard. The reason for my suspiciaon is that there is NO projector that can work at 48 vertical pixels. Furthermore, there may be no arena display systems that are even able to play back a display of 48,128 horizontal pixels. They usually need displays that aren't as wide, but are crafted to look as if they are a single continuous strip.
You should check with your client for the delivery specifications needed by the arena's playback equipment.
I would layout your comp at 1/2 or 1/4 size exactly, then split it up into 47 different comps I would then run the resize composition script on the 47 new comps to make them full size. This way you can fall well within the max horizontal resolution of AE and still render out full resolution clips.
I hope you followed that logic. What ever way you try this project it's going to take a bunch of system resources to pull it off.