I really like the idea of copying the invitation but that might not be what the OP has in mind.
Some of my friends have lovely wonderful expensive embroidery machines with scanning capabilities. They would be able to take particular words and phrases and embroider them to a large scale so long as it fit within their hoop.
I would think that even if you didn't have friends with expensive machines if that was the route you wanted to go you could find a local home embroidery business that wouldn't be too horribly expensive, especially if you provided the fabric.