I do have a theory for the use of name Saito, the character played by Ken Wantanabe. (**note, I also consider Ken Wantanabe to be Suri Cruise's real father...but that's another theory)
Saito is a popular surname, and there are a number of famous Japanese that bare this name, although I think this name choice for Inception comes from a connection to a popular film character.
Colonel Saito in The Bridge on the River Kwai
In the Oscar winning film, Sessue Hayakawa was nominated for his role as Colonel Saito (pictured above).
Saito plays a very harsh domineering Colonel over a Japanese camp, where he forces American and British prisoner's to aid in building an important bridge for a train during WWII.
Saito shows no regard for the rules established by the Kyoto protocol, requiring all men to provide manual labor on the bridge.
In Saito's mind, it is very clear that there are only two results, success and failure. If you succeed you live, and if you fail, your only choice is to commit ritual suicide.
As just one part of a very exciting climax to the film, Saito is stabbed and killed.
Saito in Inception
If Colonel Saito is the one who is driving the mission and pushing the schedule to make sure that the bridge get's built, Inception's Saito is the same unstoppable driver in this film as well.
Not only is Saito over the mission, not only is he aggressive in his nature, he is also anything but hands off, and makes a point to be a long for the journey, to make sure it goes as planned. (Although, he's initially deemed 'The Tourist' in the mission). This emphasis on being along for the journey and his role through the different levels of dreams certainly plays it's own role, but there is certainly a similarity between the drive of these two men.
Not only that, Saito's set up of having Cobb (Leonardo DiCaprio) on the plane to LA sets him up for a succeed or fail situation much as we see in the scenario set up by Colonel Saito in Bridge on the River Kwai.
And if this is Nolan's intention, surely the 1957 British WWII film has two images that seem appropriate to this film. One is the bridge, which we see in this film as part of "the kick" in one dream, and then of course, there is also the train image, which we also see in these two films. Although, not necessarily associated with Saito's character.
Was this connection and naming between these two characters intentional, or perhaps the reference is different? It's a little less clear than the Ariadne connection, but to me this seems like a rational thought in the Inception name game.