[Update: here it is!, and here's a better version (thanks Mike)]

MGS4 now has a name: “Guns of the Patriots”.

At the TGS, Kojima Productions has been showing off a new MGS4 trailer, though I haven’t found it online yet. The trailer shows a shattered street full of advanced weaponry used be futuristic soldiers. And older, wiser Solid Snake takes the fight to them, downing them with precision and skill. Then as more enemies approach, Solid Snake takes refuge among some debris.

Not much to go on yet, but IGN has more information from Kojima Productions.

PS3 IGN – TGS 2005: MGS 4 Seen, Detailed