Did the Okinawans develop their own belt system?

Apparently, yes. It may have been somewhere around the 1960's or so. There is not much documentation other than the word of a few but as to the system Isshinryu there are a couple of black and white photo's of Tatsuo-san wearing what appears to be a red belt with a gold stripe through the center. The photo of Tatsuo-san is dtd around the mid-sixties, i.e. 1966 - 68.

It would be nice to see the entire belt system from the Okinawans but alas all my inquiries have been, to date, ignored. The belt system seems to have fallen out of favor since the sixties and except on rare occasions the Okinawan karate systems seem to have remained with the generally accepted belt system based on those passed to us from the Japanese Judo system by Kano Sensei. 

Okinawan Dan System

1st - 3rd: black belt with silver strip in middle lengthwise

3rd - 6th: black belt with gold strip in middle lengthwise

7th - 9th: red belt with gold strip in middle lengthwise

10th: solid gold obi

1961 era development; not fully validated from any official Okinawan source to date.

Click for a larger view of this photo.

RyuTe RenMei: These type of belts were issued by the Zen Okinawa Karate Kobudo Rengo Kai. In this case "Zen" means all, as in all of Okinawa. Shortcut, All Okinawa. This organization existed between 1965 through the middle 70's. The belts were characterized by silver or gold stripes. The silver was for 1st and 2nd dan and gold for 3 through 6th dan, all on the black Obi. 7th and up was gold on red. The size of the stripe increased with the rank. ~ November 7, 2010 at 2:00pm FB Wall