Hey! I think a honeymoon registry is a great idea - or any sort of non-traditional registry. We used http://www.wanderable.com/pages/honeymoon_registry which is a free and pretty site, with no ads. It lets you put in whatever you want, so we did include a few traditional items to our registry, and also an area for donation. Unfortunately, it doesn't go directly into the charity, but whatever was given specifically to a charity, we made sure to donate after.