I'm something of a fiend for small guitars.
I've owned the following:
Martin Backpacker: Wins for portability, but it's the furthest from a real guitar.
Gretsch Americana: Small enough to take places you couldn't take a dread. Fairly rugged, very affordable. I bought 4 when they were on sale for $50. Three play great, one won't stop buzzing no matter how much truss rod adjustment I try.
Larrivee Parlour: This is a real guitar. It might be small, but it sounds better than many full size guitars. I bought it back before they made them all fancy and tripled the price. It was supposed to be my travel guitar, but it's too nice. In fact, if I could keep only one of my flat tops, this would be the one.
Emerald X5: Carbon fiber + tiny size = the ultimate in portability. No worries about temperature and humidity, and it's not much bigger than a tennis racket. It isn't as loud as a full sized guitar, but it's loud enough for a camp fire, and plugged in you'd never know it's so small. However, I just haven't bonded with it, so I'm planning on selling it (PM me if you're interested).
Walden T550: Like the Larrivee, this is also a real guitar. It's my brother's main guitar. It sounds smaller than the Larrivee, but it costs a lot less too. It's a very decent instrument for the price, and not too much of a compromise from a full sized guitar.