How to handle relatives that aren't invited?

I'm having a small home wedding (expecting around 25). We're only inviting parents, siblings (and their kids) and grandparents, plus a husband/wife who have played in important role in our relationship.


I tried to break the news ASAP when I told my relatives about my engagement. They are all understanding, even though a couple seemed a bit disappointed.
FMIL would like me to send invitations to her siblings, and said they wouldn't come (they're halfway across the country). I'm not going to risk inviting an additional 14 people on the assumption that they won't come (it would also entail adding 26 on my side, and about half of them would come). BUT I would like to make our aunts/uncles/cousins feel special even when they aren't invited.
Is there any "alternative" I can do for my FMIL's siblings? We're getting right before Thanksgiving, so I'm thinking our Christmas card can be/have a wedding photo, but apart from that, I'm stumped.