ULTIMATE GIMMICK SET COMING THROUGH
Well not really, since it would be kind of hard to top the OP's PP-stalling set. In fact, I think this has a bit of potential.
"Curse of the Bananasaur" @ chesto berry
calm - 252 hp, 252 spdef, 4 def
- fly/whirlwind
- leech seed/whirlwind
- curse
- rest
Tropius' defenses are surprisingly good (99/83/87), not to mention it has crappy speed (51), so he can actually make decent use of a curse set. Curse is for boosting defense and attack, while infinite chesto+rest is the perfect healing solution. Leech seed is favored over toxic as it not only wears down your foes, but also heals Tropius while he boosts or attacks. Fly is there mostly because Tropius lacks a good physical STAB (leaf blade can't be used with curse), but it also has the added benefit of giving Tropius a free turn of leech seed stalling. Fly has an acceptable 24 PP, as well (15 without PP maxed out). As for the grass types that are immune to leech seed, fly is there to hit them for super-effective damage. If you're afraid of being set up on (substitute users could cause this set a lot of problems), then you can always run whirlwind in either of the first two slots. I wouldn't really recommend choosing it over fly, though, as Tropius can pack a reasonable punch after several turns of boosting its attack.
Chesto berry is chosen over lum berry since it prevents the scenario of locking yourself into rest for an extra turn (if your opponent uses a status move before you can use rest).
Of course, this set's far from perfect. Taunt users and phazers still deal with Tropius quite easily, and pokes with herbivore ruin the idea of leech seeding. Also, as stated earlier substitute opponents are a bad matchup for leech seed and fly. And there's also that "always crit" ice move, which is basically a sure-fire counter for this set. But beyond that, I think it has potential, at least in lower tier matches. And there's always heal block, but who actually uses that?