Yep - Jason Engle is a seasoned pro and is work reflects it. However there are many people working on character design like that who are starting out. The best bet is to find a price that works for you and post a note on ConceptArt on the small freelance board:
http://www.conceptart.org/forums/forumdisplay.php?f=130

Another option is to tap Hugo Solis (http://butterfrog.deviantart.com/) who I know is good and reasonably priced, but is very busy. Good luck finding someone for your illustrations! Hope those two sites give you a good start.