I wish I had time to make a mod out of this myself, but I don't. Here are some correctly proportioned leader images from The Ur-Quan Masters HD, available under the CC-BY-NC-SA 2.5 license. I'd love to see a mod made from these. 
Leader foregrounds: http://imgur.com/a/iCNcD
Leader portraits: http://imgur.com/a/NpVAd
