My file generating the most requests has been one of the very first I designed for the Silhouette store. It was designed for a very specific long skinny wall in my laundry room. It is one of my favorites as well and I finally have transferred it to SVG, pdf and dxf formats.
It took a while because my designing skills have improved and I wanted to re-do all of the engineering of this project. The boxes fit together much more closely and I have added the cut numbers to help identifying layers and locations. It makes following the directions much easier.
The file can be purchased here:
http://www.3dcuts.com/shadow-boxes-nature-themes/birch-shadow-box-in-4-parts
You can check out the tutorial before you buy here:
http://www.3dcuts.com/tutorial-birch-tree-shadow-box-1
For those of you with no cutting machine - consider this file as one that can be completed by hand cutting. Just use the pdf files. I'd probably have the lines of the tree back come into a straight point but the rest is very easy cutting.