My roomate and I went as weekend at bernies a few years ago. It was pretty easy to do. We got all the clothes from random places on the internet. I made the Bernie mannequin using mannequin head and hands and then use some 1x1 wooden beams to make a rough skeleton. I then wrapped that in bubble wrap, tied it all together with duct tape and put the clothes. Then painted the face and stuck on the wig, mustache and glasses.