Here's one that I alluded to in the OP.

Suppose with 100bb stacks it folds to Villain on the button who opens to 4x. Hero 3-bets to 12x in the SB, and the BB folds. Villain's options are to 4-bet to 32x or fold, and Hero's options if Villain 4-bets are to 5-bet to 100bb or fold. Finally, if Hero 5-bets then Villain has the choice between calling or folding. If Villain folds, the flop/turn/river is dealt and there is a showdown.

Now, suppose Villain raises with any Ace, any two cards 9 or higher, and any pocket pair, 4-bets with TT+, AQ+, and calls a shove with his entire 4-betting range. How can Hero maximize his value?

After you figure this out and start to get a feel for how adding different hands to different ranges will affect Hero's value, change Villain's ranges and do it again.