Just a thought .....along the same lines.....we'd decided we didn't need Jerry can holders after we got the patrol with the extra tank but did investigate holders "just in case".
We found one advertised on flea bay which is still a possibility for us.....we have no spare space on front or rear of the van .....this one was a collapsible holder which was attached to the bar, travelled flat without interfering with the bed ends .....but broke down to an entirely flat unit when it wasn't needed....and the sides lifted up to brace the Jerry when it was needed.
I haven't looked for a while but it was listed as " collapsible Jerry can holder"