Maybe I could see the lower end of that.   Certainly you need a designer that is top notch - but that should be 2-3K, right?  And the person that implements it, you will want to have someone who has solid wordpress skills on staff.  Yes, they would need to be paid for their time, but again, that should be 1-2K, right?   What am I missing that would bring it to the 20K mark?