Me, too. Trump is predictably unpredictable, and this is way too easy.
Who are the others we're not looking at? Sessions, West, Hunter, ...
If he picks someone off the radar, I think it'll be someone who came out publicly to support him early, back when Cruz and others were still in the race. Trump values trust and people who aren't afraid to "go against the grain," and early supporters fit that requirement.
Duncan Hunter Jr. was the second congressman to come out and support Trump. Perfect fit—Veteran, Congress since 2003 solid conservative and a chip off the old block. BTW he is young too.
Sessions!