The only thing holding me back from playing Oblivion. Was one ever made? Will one ever be made?

And if no one makes one, where can I get some jungle assets?

TWMP Valenwood Elsweyr, by Under The Sign of The Dragon adds a jungle in Valenwood. It requires TWMP heightsmap and Elsweyr Anaquina (2010 version) as masters.

This is just speculation, but... I saw Brittainy, the author of the Lush and Gaudy series, upload some "tropical" screenshots to her nexus gallery that have since been removed, my guess is she's working on a tropical/jungle themed vegetation replacer.