Where can I find people for hire with LaTeX skills and designer skills?

TUG have pages for both 'consultants for hire' and 'jobs advertised. You could consider using these to find the appropriate person.

If it's hard to find a LaTeX capable designer: you could hire a good book designer to develop a great look, a skilled LaTeX user can help to implement that.

Anyway, you can ask LaTeX users in web forums, Usenet groups and Q&A site listed here: Good resources on-line for information about TeX, LaTeX and friends