I spent most of the summer working on this Murphy bed for the bonus room. I kept thinking I would post pictures once I installed the mattress, but the mattress is currently in Calvin's room where we've been snuggling in the morning to put him back to sleep longer, so that mattress is staying put for now.
I used some Ana White plans and then modified them to fit my double mattress. I also added a massive magnet and a cam lock to keep kids from opening and closing it.
Since the original plan was for a twin mattress, I needed to attach two pieces of plywood together to make a platform large enough for a double size to rest on. I used glue, pocket holes, and mending plates to add a piece to the side and top. All-in-all it's pretty sturdy.
Once it was painted and mending plates were added.
The main frame was bolted into the studs.
The platform was attached with door hinges
The molding on the front is just 1/4" Maple plywood ripped into 4" and 3" strips. They were strategically arranged to cover the seams where the pieces were screwed together and they give a little more reinforcement.
Here's a peek at the current construction zone in my house: