Speaking only for myself I lost count of the covers I've made at a little over 1,300. With time being an issue . . . going back an remaking a CD version of each is not something I would look forward to. I try to keep the exact original cover image editing only the stickers and logos for the developer/distributor due to one or both changing over the years since the current GOG release. I can then replace those logos, add GOG's, with the current dev/dist logos. I considered keeping the original dev/dist logos but felt that was not fair to the devs/dist releasing games on GOG today. Since the CD covers are smaller that would mean editing a larger area of the finished image which can be very noticeable depending on the original image quality. Finding high quality images can be difficult even for newer games.
I did make one CD cover on request and found it difficult to add much info to the cover due to the small size. I ended up just using the original front and back cover image which meant double the image editing/repair. I appreciate your desire to have CD covers but I myself cannot commit to making new/old CD covers. Sorry.
With external storage being very affordable I would suggest you get a good quality external for your actual backups. That's just my way of backing up my games for some time and no dis on using CD/DVD's if that is your preference. I store game covers with my game files just to have game info and an image of the front covers I spent so much time looking at back in the day.
Other folks may be willing to take on the challenge. =)