I'd rather implement voice recognition with waveform pattern matching and skip some silly finger gesture altogether. I want to be able to say "Open sesame!" and ZING! I'm in.

Other touch/gesture ideas which may or may not be practical to implement:

1. uNlock: Rather than a simple swipe to unlock, spruce it up with a big (or whatever size is reasonable) N graphic that you draw out in one stroke.

2. ROYGBIV: Generate a pattern of touches that use colors to distinguish one from another, along the lines of the Simon game of yesteryear. Get real sophisticated and have a dynamic element that will change the layout/order of the color buttons on the screen so you truly have to memorize the color pattern, not just the physical location. (so one time you unlock it red will be on the top of the input image, the next time it may be to the right or bottom)

3. Fingerword: I still think we need to be able to record continuous input from the touchscreen and be able to access it/replay it/manipulate it. For the purpose of an unlock function, using a touch-input recording app (maybe someone can crank one out if it doesn't already exist) you'd simply draw out your unlock pattern on a screen in one stroke (or if the app is capable enough, maybe multiple) which is then stored and retrieved for matching when you go to unlock your device. So you could use a "pin" of 4 or more digits but rather than entering it on a keypad, you'd be writing it out (invisibly) onscreen. Or you could draw a simple picture (invisibly) or write a word/name or whatever you choose to be your fingerword..

4. Moveword: Take the cheat code ideas from console games and apply it to the accelerometer- record a pattern of movement that has to be reproduced in order to unlock the device. Such as tilting the N900 forward+backward+forward+backward+left+right. I wonder if spinning could be captured and mixed in? Simple/short movewords may fail in the real world with everyday jostling and handling of the device.

All but the first idea fall into more of a security integrated design than a simple unlock function. But with a touchscreen interface, open source, and the great minds of the community there's no reason something more creative can't be put together.

Forget passwords, we want new ____words!