wikipedia said:
http://en.wikipedia.org/wiki/Vietnam
me said, "small" nation like a barbarian if compare to united china (china is english name, in vietnam china mean 'center of the world', 'center of best thing'). They capture us for about 1000 year but we have our private culture, so the last revulation become success.
after that, the france with hi tech come to conquer the poor closed door barbarian and again, 100 year late with right tech from Xoviet, we take another success revulation with the famous battle Dien Bien Phu
http://en.wikipedia.org/wiki/Battle_of_Dien_Bien_Phu. but mighty American take control of south vietnam and it make a war long for 30 year. Who win, you already know.
in civilization game, its' very interesting to play hard level, your civ weak first but last stand. But if you have to stand again a mighty military, you will lose easy, not true in real life like in vietnam, vietnam's infantry can hide and take health in its town, cottage and more, its' town or cottage can procedure military too (with neccessrary condition)
so for vietnam civ, I suggess:
Leader: Ho Chi Minh
Traits: Aggressive and Philosphical
Unique Unit: Infantry (Can hide and take health in town, cottage, hamlet <of its mother country>)
Unique Building: Town, Cottage, Hamlet (can procedure military, if the city is capured, town still can procedure military)
Fave Civic: Police State
ps: I think only have special UU, vietnam can stand again China, France and mighty USA