as ysss wrote "On the iPhone\Touch it seems that the slider is designed as close as possible to the activation button (home button, directly below the screen on portrait orientation) with the natural input gesture as minimal as possible to unlock the device.. with a single finger."

i think a swipe on a resistive touch will not be detected as smooth
as on a capacitive touch.

I dont have a Iphone but i have an Ipod touch.
I preorderd the N900 already and cant wait to have one.

If there is no way to disable it and i still dont like it after i hold the phone in my hands i can try myself in editing the maemo soure :-)