I am writing a thesis on the textual differences between the LXX and the Masoretic text in 1 Samuel 16-18 (1 Kingdoms 16-18 ). You can read a very brief sketch here.
It should be an interesting study, and I have yet to reach a conclusion. I chose the most provocative working thesis: The MT is a conflation of the proto-Hebrew (as reflected in the LXX) and some later Davidic tradition. Like I said, I am not sure that is what I will find, but it is a possibility. Another option is that the LXX translator(s) applied a heavy dose of editorial discretion for some reason.
Has anyone else looked at this issue? Anyone care to make a wager?