this one i made not a very good pic though, i spent a few hours shaping a cardboard templete then cutting it out of 6mm MDF, i wanted better speakers as the stock rear speaker are quite poor so cut those into the MDF
then covered the top, wrapped the edges then covered the bottom in accoustic cloth which matches the factory carpet perfectly (applied with 3M spray glue) fabricated a little cloth handle so it lifted easy, and a velcro hinge. Then made a little sneaky pete in 3mm lightweight plastic, and this velcro'd on/off the accoustic cloth
i also did some quick release wiring so the shelf and speakers could be removed quickly from the car when required and the factory stock speakers would come back to life
i also sometimes had it rigged with cords attached to the stuts so that it would lift automatically when the hatch opened
once i showed a few guys in the club they wanted one as well so i knocked a few out, including 'Big Vipers'