I was thinking I might try to make a boot liner out of fibreglass instead of the usual MDF ones, assuming it will be lighter.
I was thinking of using strips of MDF to make up a frame to fit in the boot, then removing it and putting fleece over the outside, coating in resin until it's hard, then removing the MDF frame and fibreglassing the inside.
A few things I'm unsure about at the moment, mainly that the boot opening is smaller than the boot so the finished article won't squeeze through it.

Also, where on earth sells fleece?
I've read about sub boxes and big units that replace the rear seats as well as the boot space, but nothing about just boot liners. Has anyone else done this? If so, how?
Any suggestions about this would be greatly appreciated,
Cheers,
Matt