I created this custom invitation when I worked for an in-house marketing group. Our company took our top producers on an annual cruise and each year I was in charge of creating all of the printed and promotional materials. For this year's theme, I chose to include my personal love of antique maps. The invitations were 5.5" x 17" and were tri-folded and sealed with a custom made wax seal that featured the company's logo.
Oh, and in case you haven't figured it out yet, the image on the left is the outside of the invitation.