I made my own, as well, out of a large aluminum drip pan. Just measure it out, cut to fit for the driveline hump and the side interior trim, drill holes and place your screws, remove it, paint it, and bolt it back in. Done. Took me about 3 hours to do mine. Only reason(s) I got rid of it was because I got sick of the amount of noise it allowed to come in from the rear (mostly exhaust noise) and because I needed to use that big piece of sheetmetal for another project.
You can score a decent-sized drip pan from most auto parts stores for less than $10. Add screws ($2) and paint (depends on what you use - Herculiner would be cool for a durable, textured look), and you're looking at *MAYBE* $25 total, and it weighs practically nothing at all.
FWIW, when I weighed my upper and rear seat cushions with a scale, they came out to somewhere around 25 lbs. and the seat delete panel was about 5 lbs.