Hi, your task made me very interested!
I'm designer and illustrator, and in fact designing the greeting cards is my prime business. There're some of my works in my profile and it would be great if you check them out.
I can make the design in Ps or as a vector image in Ai, it's just up to you. If maybe there's a need in a test free design - you're welcome :)
Kind regards,
Masha