No screenshots just yet, but I have finally gotten to work on Chapter 4's super-secret optional area.
It's made up of a city, a castle, several small wilderness areas and caves, a creepy forest (full of creepy pine trees), and a tower inside that creepy forest where the most powerful of the area's
five optional bosses lives. So it's basically an entire chapter's worth of stuff jammed into the already-huge Chapter 4.
There will be a handful of new items you can only find here. For example, there's an item that changes the appearance of your characters... well, three of them anyway. Señor Rialgo is just too damn big to fit in the suit. There's also the "Magic Sauce," which can be used in battle to increase all of your main stats (Attack, Defense, Power, Wisdom, and Speed) by 33% each. You're allowed to buy one Magic Sauce, but if you want more you'll need to steal 'em from a certain enemy in the area.
Speaking of enemies, the random encounters that show up here are tougher than any of Chapter 4's enemies, or even most of Chapter 5's. A couple of them use some pretty neat tricks, too--there's one enemy that can use both "Mitosis" (which spawns a copy of itself) and "Fusion" (which kills it, but gives all of its HP to another enemy, increasing beyond the maximum if possible)... so if you leave one alone for too long, it could spawn a whole army of them and then combine all of their HP into one ridiculously huge amount. Or worse, they could all give their HP to a tougher enemy and leave you with a real monster to deal with. There's also one that uses jump-attacks on you, one that can give its allies Magic Sauce an unlimited amount of times, one huge one with 400 HP (the most of any random encounter so far, though it will probably be dethroned by a certain rare Chapter 6 enemy), and the strongest type of cockroach in the entire game.
If you do manage to get through everything, you'll be rewarded with at least one item for every character (including the most powerful weapon El Garbanzo can find.) That's on top of the buttload of experience and money you get from fighting the five bosses, of course.
EDIT: The "town/castle" outside area is coming close to being finished! I'd say the central city part (around the castle) is just about done, though there's still a ways to go before I'm completely finished.
Maybe a half-dozen or so more houses, some extra wilderness around the east and south edges (there's already some pine forest up at the top), and a cave entrance over to the west... and that's all I have left for this map. It'll probably be Wrongside-ish in size by the time it's done (with one big difference: there's no random encounters unless you wander into the wilderness areas around the edges.)