My character names come from all over the place. If the name wasn't obvious up front (I don't know why, but sometimes it is - or seems to be, but sometimes I'm wrong), then like you I tend to use place holders while I get to know them and then settle on something later. Otherwise I use anything from babynames.com (lets you easily see where the name is from and what it means etc), to my own database of random names, to adaptations from old myths etc., to simply "oh, that sounds good/right".
However, in a situation like you describe, I turned to imdb
In my first book I had a character that I knew almost exactly what I wanted: a very young Tony Curtis. That young, slender, bright eyed and cheeky little boy look he had. And I knew I was remembering the particular look from some movie that I hadn't seen in years ... turns out it was Taras Bulba (also starred Yul Brunner). And so I got my character name from the part he played in that movie.