Have you tried the Embedded Embossing technique? It's a really fun thing to do and it makes mailing your cards even easier as it creates a single layer. All you have to do is die cut your favorite images, adhere them to your base cardstock, and run them through an embossing folder. The tighter the pattern is on the embossing folder, the better it will turn out.
What this does is embed the top layers into the base layer. Pretty cool, huh? Here's a close up so you can see what I'm talking about.
The Butterfly Flourish from Die-Versions now becomes part of the pale pink background as does the sentiment that I cut out using the A Little Lime Die-Versions font. I added some gems to the flower centers and a bow, but this is still basically a flat card that can easily be mailed without any extra padding or postage.
Don't forget to check out the Die-Versions blog to see what the rest of the team comes up with using all the Die-Versions dies. There are some pretty amazing projects on there!