A while back I saw this post on Geekhack about the numpad GH80-3700 from Cherry. Long story short: I wanted one, too. Since they’re no longer manufactured I created a listing notification on eBay and got lucky after a few months.
Time to start modding: I cleaned everything, bleached the case, modded the existing Cherry MX Black switches, replaced the PCB and plate and finally soldered/assembled everything back together.
Check out the detailed list of modifications, image gallery, (semi professional) before & after comparison and the short video of the startup audio below!