Here's a card I made for a friend's Baby shower, she had twins-a boy and a girl. It was a lot of fun to make and a big hit at the shower.
SC110 Twin Bundles of Joy by mom5boys at Splitcoaststampers
I used the scallop punches, but they could be cut out with decorative edge scissors as well. Maybe you can enlist some help with the invites.
Good Luck on finding one that works for you and congratulations on the twins!