Ummm what's wrong with a changling rogue or factotum? CHR is nothing compared to detect thoughts. Why not get a half fey template so you can charm at will as well? Detect thoughs and charm should give you at least +4 circumstance bonus on social checks, since you are a changling you might get another +2 racial bonus on them as well.

skill ranks >> CHR modifier

You don't need a high CHR to be a conman, its a nice bonus at early levels but when push comes to shove, skill makes more of a difference.

That being said, beguiler has some nice spells like suggestion, telepath can use a simple attraction, or even dominate, wizards can mindrape...... I'd say flavor wise rogue just fits the best, you get enough skill for CHR to not be an issue.