So, I know of
http://www.ocdreproductions.com/ , making NES, SNES (US) ,GBA and Megadrive reproductions, with fancy labels and colourful shells.
http://www.retrousb.com/ , editing NES homebrew and making reproductions of stupidly expensive NES and SNES (JP/EU shell)
Nintendo World Championship games, in transparent modern shells.
https://pceworks.wordpress.com/ Fancy reproductions of PC-Engine CD games
http://www.nesreproductions.com/ is specialising in putting translations into your original NES/Famicom games. A donor cart needs to be provided for any reproduction order.
What else?