Hey there! I've recently put in an option that allows streamers to request a free offline wallpaper for their stream made by me and others! We have thought of this for a while now and we finally implemented it!
The way that "Stream Request" works is that you put in details about your stream, what games you most often play, how many viewers you usually get etc BUT, the "Stream Request" has requirements:
1. Have 75+ followers
2. Stream twice or more per week (to show that you're dedicated to your streaming)
Anyway, that's about it, not that much more, you can add in details you want and stuff that you want in the wallpaper.