I reshelled an old scruffy GameBoy Advance SP as a gift for a friend. Here are some photographs of the process.
The finished product!
I got this second GBA SP with a broken shell for a cheap price and repaired the shell with glue and duct tape. I will reshell this at some point but for now I have a spare working GBA SP.
It works!
Update 25/08/2020: Finally got around to reshelling this GBA SP and taking a picture, here's the finished product with a NES-style shell:
Let me know if you're interested in buying this!