I did this mod on my Gulfman a few months back.
Mod consists of...
1) Stealthed bezel from the G-9100
2) 16mm to 22mm NATO adapters from Keoni. These are molded ones, not the 3D printed ones he also sells.
3) Stealth Bond seat-belt NATO from Cincy Strapworks. I modded the strap with PVD hardware.
4) Removed most of the yellow text inside the crystal. I left the "P.SAVE" line intact but removed the RC and BATTERY text from the sides and RESIST text on the top.
5) Painted the red accents on the face in gloss black.
6) Heat anodized the titanium corner screws.
7) Heat anodized the titanium bezel insert after having success with the screws.
8) Airbrushed the G-9100 black plastic insert with transparent blue so it would match the blue and purple titanium a bit better.
9) Strengthened the NATO adapter and lugs to resist breaking.
It originally looked like this.
and with some bullbars
G-Shocks have ruined me for "real" watches. They're pretty much all I wear now. The accuracy and indestructibility really appeals to me.