No, Hunter does not have a design service. However, they have a pretty good residential design guide that any competant DIY'er could easily follow and understand.
http://www.hunterindustries.com/Resources/Design/design_guide.html
I agree with Tom that it really helps to see the property to do the design. Unless you do a super-detailed plot plan, it is hard to lay out a good system if you have never seen the property.
