If we're going to use women's bodies as metaphors for laptop cases, I would contend that the Titanium is like a pasty-white 6' 2" 105 lb supermodel--beautiful, but fragile and not terribly versatile.
The Pismo is more like Pamela Anderson. Smaller, curvier, sexier, but a bit studier. Hey, she was married to Tommy Lee for years so we KNOW she can take a punch, right? Just like a Pismo.
As I have already stated ad nauseum here on these threads, I would love to see them return to black polycarbonate. Maybe titanium reinforced on the corners with supprts cast right into the poly. Then put in a true 16:9 display for killer presentations. I wouldn't care if it was two feet wide. And I wouldn't WANT it an inch thick, unless it were milled out of solid aluminum, because I want to use it in the bump-scratch-and-drop real world, not the land of "esoteric design utopia" where laptops are never dropped, bumped, twisted, scratched, handed from one person to another, or even touched.
I hear the Japanese don't like TiBooks because they are too wide to comforably use on their subway trains. I say give them 12" iBooks w/processing abilities at near TiBook levels. For the travelling film/graphic arts/web design professional, however, give us a big platform, durable, versatile machine again. EXPANSION BAYS! Yes, you can hook up peripherals via FW all you want, but I don't want to bring an octopus to a presentation. I would rather hot-swap whatever I'll need (CDR-DVDR, extra battery, extra HD, etc) ten minutes before the meeting and have an elegant platform to work from.
Take a Pismo and just add four inches of width to the case and the screen. Make room for 2 G4 processors and DDR RAM. Keeps the bays just as they are. SuperDrive in one, battery in the other. Keep the excellent output options, plus an additional DV out for Apple external displays (not that you'd need one). Reinforce the chassis w/Titanium supports and gel-suspend a g-force resistant HD for hard portable usage.
Now THAT would be worth $3500-4000 in a portable...
(..slowly waking from the dream...)
Huh? What? Did I post something?