Those of you with relocated tanks.. What to do about the stock tank?

[chevy72blu]

I have a Boyds EFI tank under the bed, that I installed when I did my LS swap.

The thing is, my paint is still in decent shape and I dont want to weld in a cover for the hole that the tank would leave.

So, for years I've just left the empty stock tank in the cab. I'd like to remove it for more room and to add a subwoofer back there.

I was envisioning cutting the filler off from the tank itself, and then securing it to the cab. The gas cap is lockable, so I'd just toss (or hide) that key so someone doesnt try to fill up there by accident.

Anyone have any pics, or tried something like this?