If you are one of the people who find the G-9100 Gulfman strap to be very uncomfortable, I have a possible cure for you. I tried a DW-9052 strap last night, and it fit perfectly on the Gulfman without modification. The DW-9052 strap is very similar in both shape and size to the stock G-9100 Gulfman strap. It doesn't have the lettering on the strap though, and more importantly, it doesn't have the second row of ventilation ribbing, that can really bite into your tender wrist. If your only complaint against the G-9100 strap is that nasty second rib, I strongly suggest that you give the DW-9052 strap a try. I will attempt to take pictures late this afternoon, and post them this evening. The strap is very close to a perfect match for the Gulfman case.
It also looks like many different Casio straps will fit the G-9100 Gulfman. Basically, just about any non-resin strap should fit. I tried a DW-004 style leather/nylon strap, and it also fit quite well.