I've been taking long looks at Carole Marine's marvellous blog of daily paintings, especially her set up which she has generously explained in a couple of posts.
This set up is excellent for controlling light [and for adding a touch of sunshine which we so seldom get in this country!]. According to Carole, her husband cleverly contrived a frame by using electrician's ducting, which is both rigid and light. Perfect for moving around the studio or even collapsing to store. So, well done Mr Marine!