I agree that I'd much rather pay to go somewhere amazing for a wedding than...back home. For me, FI and I are about 12 hours from "home" and a friend is getting married there this August. If I wasn't going to be here MOH, I honestly don't think I'd be going back because I found out my plane ticket to get there is going to cost the same as my flight to Hawaii!!
Great deals can be found in HI. My family, which is my parents and 3 siblings, got their trip package for under $1000 a person and then plan to eat at the inexpensive places such as plate lunch spots and such (other than what we're covering for them for wedding festivities of course!). My family has never taken a major vacation (it's always been camping in the same state, etc) and were we not having a DW, they probably never would, so this is a great excuse for them!
I think the people who mean a lot to you will work hard to get there. If you have a wedding website, include tips for ways guests can save, or even include this in your invitations. We found Maui Revealed (the book and their website) to have amazing tips and advice, as well as Frodors. Good luck! No reason to feel guilty! I felt that way at first too, and it's hard when most adults are choosing not to bring their kids, but I figure for me, I'll come up with something a little special to do for those kids at our AHC.