I bought these beautiful Kraft paper "Simpson" recycled envelopes (slightly smoother and more chocolate-y than regular Kraft paper - very elegant) before we chose a different invitation color scheme. They would look great with white ink handwriting/calligraphy! Would prefer to to sell all three together.
Here's the link where I purchased them:
To see the approximate color/image, make sure to select the size A6 (4 3/4" x 6 1/2") from the drop down box. It's Item #30003.