Depending on how big your GLO is and if you have a Banner or flag, your best bet is to do it yourself.
The one I designed as a local was done by hand.
If there is enough interest as SNBullet said contact a flag maker.
One in Kansas City, Mo. is either National or American Flag Company. I know they are not really that cheap, but quantity makes a lot of difference.
Go to AT&T Yellow Pages and look there or try Kansas Citys as there is @ 8.
Might even be some in your area!