Melted crayon projects have been all over Pinterest and would work great as a switch based project for learners with intensive special needs.
Most versions of the project on Pinterest call for using hot glue to attach the crayons to canvas and then using a hair dryer to melt the crayons. For a less expensive version, mount on rectangles of some fore core board and use black masking tape covers the cut edges. Use some left over silk ribbon attached with more hot glue to hand
The project can adapted for the students, of course. Students can spend time choosing crayons and creating their pattern of colors. They also can choose their silhouette or image to add. Staff should hot glue the crayons on the fore core board, of course students can use AAC to shout, "Ready, set, glue!" and "stop now!" Next up is fun with switches! Hair dryers can be attached to an environmental control box (a Powerlink) and switches can be used for the students to control turning on and off the hot air.
Variations on the melted crayon project include different silhouettes (hand cut or from a Cricut, arranging the crayons in shapes like hearts, having the crayons melt "up" and turning them into flowers, using stick on vinyl letters to write a name or word and then carefully removing to leave a print behind and more! A quick Google or Bing images search for melted crayon art should show you lots of choices!