I highly recommend making a character portrait tailored to what you specifically want. Sure, you can find one, but if you make one (or get one made) I will award you with in-game bonuses, somehow.
If you do want to commission something, and have no idea where to go, I strongly recommend this guy: http://bchart.deviantart.com/journal/Commission-Info-Closed-until-March-25-2017-430796321 (or if that link is dead, try this one: http://bchart.deviantart.com/journal/ )
I've worked with him before and he's great.
$40 for a waist up colored image like this: http://bchart.deviantart.com/art/Female-Tiefling-Fighter-565930486
$40 for a full body line-art like this: http://bchart.deviantart.com/art/Ka-en-Fire-Genasi-Bard-Line-Art-649289120
$60 for a full body full color like this: http://bchart.deviantart.com/art/C-Gordie-Halfling-Fighter-Rogue-655347343
Well worth it, in my opinion!
If you reach out to him, let me know (because I can give you his direct e-mail) and/or mention me and the game, I told him he might be getting some requests in the near ish future.