I went with the following:
Rubbermaid 35gal Action Packer for $40
https://www.amazon.com/gp/product/B000I1BU6E/?tag=sxsweb24-20
I found it doesn't seal well enough to keep the dust out, so I'll be creating a seal for it using some type of sticky backed foam/rubber seal. It keeps the water out.
It's a really snug fit in the rear cargo area and sits just a little off center because of the flag/whip mount on the roll bar. You can see how snug it is the in the pics below.
I removed 6 of the bed bolts and replaced them with spacers under the box and longer bolts with fender washers on top. The spacers were just stacked washers which allowed me to tighten the bolts without deforming the bottom of the box.
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