I don’t know of a service but case mods are definitely something I’ve done before for personal projects and for clients. I’ve never shipped one around before though so while I have shipped PCs before I’m not sure I would be up for doing so for a custom case mod.
You may want to just do it yourself.
Different case and I used a laptop here but same principal:
https://www.reddit.com/r/GamingLaptops/s/UpLR6xagrW