Need ideas for interior trunk panelling.

you could use some aluminum angle iron from hardware store for attaching the panels. It bends to contours real easy and can be riveted into place, then just use screws to fasten the paneling to it. You should use masonite for material, its a ***** to work with sometimes but its light, strong, and does'nt soak up moisture as much as particle board would. you just have to sand the shiny side before glueing carpet or upholstery or it won't stick.