Have you checked behind the panels in the cargo area. Seems like there is space there that you might be able to use to mount one. Just a suggestion as to a location to use. Not sure how technical or creative you are with working with wood an metal and plastic to fab something.

Good luck

1992 Isuzu Rodeo 2WD (some assembly required). "If it doesn't fit....Force it!! If it breaks, it needed to be replaced anyway."