I had been looking around for dimensions to make an equipment cabinet and finally found some here (https://www.railroadsignals.us/support/auxequip/index.htm)
The dimensions of the shed are 8' by 10'. Each of the center side panels are 2' so this should scale pretty easy to different sizes.
I used OpenSCAD to generate SVG & DXF files for each of the pieces and then imported the DXF file into Silhouette Studio. Next I place a 15x19 For Sale sign on the cutting mat. The 15x19 sign has a thickness of 0.025"
Next I used Plastruct Plastic Weld to glue the end to a side. Note the sides go inside the ends so that the roof will match the sides when it is glued. Make bottoms are flush. The top will need filed a small amount to give the right angle. This is by design so that it will get a good glue joint.
For the roof bend the styrene partially on the roof line but don't completely separate it. This will make it easier to glue the roof. Once the roof is secured place a little glue along the ridge line to glue the partially broken joint.
Hinges and door handle can be fashioned from small scraps of styrene.