Webb would be the best shot at it but in all likeliness, no. The Vietnam vets are getting old and a lot of them were turned off by politics coming home for obvious reasons so the ones that did get elected are few in number and don't have the name recognition of a John Kerry or a Jim Webb, for example.
I do think it has a lot to do with the persisting unpopularity of that war. The veterans aren't seen as war Heroes in the same way as WWII vets.
I think it's bad luck more than anything.
2000: Vietnam vet won popular vote
2004: Vietnam vet was running against against wartime incumbent
2008: Vietnam vet was nominee of party whose president had become deeply unpopular
