I've been doing some searching for you

I found this hat on Ebay, for Buy it Now. It is a Russian peak hat that looks similar in shape to the RUC hat. You would want to get a cover for it though. It says all sizes available. I would ask them
http://www.ebay.ca/itm/Soviet-army-cap- ... 19d3f734fa
And this one, alittle cheaper, this one is Large, 59.5cm. It also says that you can ask and they will try find your size.
Quote:
if you need other size ,email me,I also will have a try to help you,thanks
http://www.ebay.ca/itm/Collectable-Chin ... 2a1b553844
I also found this website, it may be pricey but you could ask them if they have 7 5/8s
http://www.bernardcap.com/marineCorps.htmHere is one of the many peak hats they have, found under "Marine Corps" (there is more under other categories, but these look like Gormans)

Some terms that I have found yeilding results, with either "Army" or "Military" before them: "Visor Hat", "Dress Hat" and "Service Hat"