Lt. General Hansen wrote:
Do you know who is doing your covers for these books? If so, they might be able to design graphics for you. If not, I would start looking for a cover designer first. Look around for samples of what you want--are there any covers from published books that you like?--and look for art styles that you like. Browsing deviantart is a great way to find reference images, styles that you like, and even artists to hire.
Browsing deviantart is a great way for me to get into trouble. I respect artists and their work but there are some places I just can't go and retain the modicum of holiness I have left.
If "Cover" is the starting point, I know someone who does that.

Wasn't sure what the best process was. Your notes on
atpollard's design were good. I don't think he's as interested in doing for the entire set as he was in giving me a really cool gift.