I am building a rear storage solution.
It is a work in progress; I hope to get some photos tonight.

I removed the 3rd row seats from my Tahoe
Purchased a 4x8 (actually 49x96 for some reason) 3/4" thick MDF from lowes for $26

Cut out the following pieces

1 large bottom area to cover the rear floor 48" wide 44" long. this will make the new 'floor'
1 48" wide 16" high piece, this will make the front so items don't come flying toward the driver when some civic cuts you off
2 43.25" x 16" high pieces for the sides. this will let cargo be placed in the new 'trunk' without damaging your new vehicle's sides, and stabilizing the front piece.

MDF is NOT water resistent. I boat, I put things in the trunk that can spill. (MDF will swell up and be RUINED if wet.

So, I found some polyuthathane outdoor clear stain in my dad's basement... and a brush.

Next step is coat all the pieces 2-3x with stain, allowing to dry between. I keep looking for newspaper to put down over my garage floor but apparently no one gets the paper anymore...

then, I will predrill all the holes and use long drywall screws to assemble the 4 pieces, since that's what I have laying around.

Next is 'car carpet' in rolls from wally world, and spray adhesive... to cover the whole thing nicely. finally is attaching some 1.5" spacers to the bottom to position this whole thing above the plastic things in the trunk.

it can't be moved right/left since a 48" wide piece is snug, and should be really snug w/carpet.

i'm thinking of removing the latch bolts in the back, and drilling a hole to and using a longer bolt to litterally bolt this thing to the truck.

ideas / feedback / input would be great as I only have the cut pieces in my garage as of now.. I want this thing to look nice and protect my truck as well as create what I had in my old Tahoe... A REAL TRUNK.... anything placed in the back of this new one will just flop forward... between the rear seats and then all over the stupid place....

 

Did you put pieces on the front and rear to prevent damage also? Curious as to why you picked 3/4" instead of something thinner and therefore lighter. This must weigh a ton.

I thought about using 1/4" luan plywood underlayment and build a frame underneath w/ several stiffeners to support any heavy items like 5 gallon gas cans, etc. Then put some side pieces on w/ hinges so the whole thing folds flat for easy storage. That's as far as I got so far.

Someone did something similar to what you did a year or so ago but their pics disappeared w/ the new software.

Post some pics when you can.

 

pics coming tonight; its in the truck and it worked great this weekend! it does weigh a bit; but its less than the back seats did... it does take 2 people to put in / out... but it should be in the truck from now on... i'm debating on selling the 3rd row still... pics by 8 or 9 tonight

 

Needs pics to get "helpful post" status

 

so, its now size is 48" wide 42" long (I think) and 12" high all the way around.

the runners under it are 1" high and run the length of it, but are back 2" from the 'front' which is the 'rear' of the truck...

I'm no appolsterrrurrr (or good spellerer) but I think it turned out ok... pep boys $30 for a 6x9 foot piece of the black carpet (also comes in gray)

 

looks good i thought about building something with drawers for the back of mine but i have not gotten around to it