I thought others might find this interestings so I'm sharing it here.

So I've been keeping an eye out for a way to carry more fuel in the space where my spare tire would go once I install an external spare tire carrier. I was looking at Titan Tanks but they don't have anything specific for Blazers. (Titan Tanks does have some tanks for mounting on spare tire carriers though.)

So I just found this new product Trail'd Spare Tanks (https://www.trailedonline.com/) These look to be sized to fit into where our spare tires are stored under the rear bumper. Each tank hold 6 gallons and two or three can be stacked together. The caveat is that they are not explicitly being sold to hold fuel; at least according to the home-page of the manufacturer. However, this review discusses using these for fuel. https://trail4runner.com/2020/05/30/...h-gen-4runner/

Whether they are used to hold water or fuel, these could offer a good way to put to use the space where a spare tire is located.

 

Looks pretty cool. Definitely not cheap.

 

Yep, definitelu not cheap.