I Hate to say it but I am 99.9% sure this WONT happen.
Here's why. There are at least one (and in most cases 2+) "leaked" foyo ROMs for each othe the US Galaxy S phones. Which leads me to beleive they are working on developing Froyo ROMs for the US Galaxy phones, and not Gingerbread.
Also, a few recent articles on Giz and engadget and a few others have posted "conversations" with various Samsung "powers" and it doesnt look likely that the current Galaxy line will EVER get Gingerbread AT ALL.
If the past is any indication, Samsung will eventually pop Froyo for the SGS line to quiet the masses (sort of). But will leave it at that and move on to the "bigger, better, and newer" and leave the current SGS line in the dust. Id love to be wrong for all you guys sake... but the chances are (at least IMHO) that;
- US SGS will get froyo (prolly in Jan) and never get Gingerbread.
- The GPS will never function propperly 100% of the time for most folks
- A few of the main features of froyo will be gimped by AT&T/Sammy
But for your sake, my friends I hope I am wrong, or atleast someone will come up with a really good custom ROM that will make this phone function (mostly) as it should have in the first place, bring the functionallity that AT&T gimps, and fix the shitty job Samsung did with the software integration.
There are some good ones out there now, even without a NON beta Froyo and w/o the source code, once those are final, I bet they will be damn good.