As krsmith said, you will definitely find support on this topic here.
We got married in May 2010 and let me tell you, my family put me through the ringer with the whole DW idea. They have never been to a DW nor did they know anyone who did one so to them it was just a strange concept. I heard for months how bad of an idea it was and how nobody was going to come. I even started looking locally just to see if maybe I could find a place locally that I would love but thankfully, my fiance had my back and helped me through the whole ordeal of dealing with my family. His family didn't have ANY complaints at all and were all super excited to come. Go figure.
My family travels at least once a year to the Caribbean and I know that they love the beach but for some reason they were very concerned that none of our friends would be able to come. They tried every single argument to get me to change my mind but I really wanted a Caribbean wedding and my husband is from South America so if we did it in the US, most of his family/friends would not have been able to come. Luckily I had that excuse to fall back on, although in reality I was the one that wanted the beach wedding.
The only advice that I can give you is to prepare yourself for some opposition and just have patience. It's most likely that nobody in your family had ever been to a DW so the concept is foreign to them and they have no idea how amazing it will be. But also, do not be offended if someone cannot come as a DW does require travel and money on your guests' parts. I told my family/friends that I'd love for them all to come but if they could not or did not want to, I would not be upset at all. All of my family and many of our friends ended up going and everyone had a great time. My family still talks about the wedding and how amazing the whole trip was and how great it was to have my whole family there together (we are spread out all across the Northeast). So just stand your ground, have lots of patience, and if this is what you really want, be ready to defend your reasons and position. Hopefully everyone will come and have a great time, then they can all eat their words