Fan-made UI concepts go hand-in-hand with iOS development, often to such a degree that some of the fantasy actually emulates the efforts of Apple’s patient and thorough system engineers. In other words, if the concept is logical and its execution kept simple (and intuitive), chances are Apple’s already playing with the idea.

Before iOS 5, the web’s most popular mock-ups sought to guess at Apple’s notification redesign. Since then, though, the general practice has slowed a bit.

But it hasn’t stopped.

The latest spotlight feature, iOS multitasking, proves some users want a better system, particularly on the iPhone. The iPad’s little (albeit older) brother hasn’t got the real estate to allow for effective multi-touch app-switching, and the idea of relying on a physical button to call up the requisite function is being looked upon with an increasing sense of disdain. Personally, I love the Home key, but–in an age of touch and tap and swipe–I certainly see where people are coming from.

And so does Max Rudberg, creator of the following (extremely short) concept video. In it, he suggests Apple allows a simple, edge-based, upwards swipe to activate the multitasking bar.

Aayush Arya of The Next Web believes the model can be expanded:

Taking it a step further, we think it would be a terrific addition if you can swipe in from the left or right edge of the display to move from one application to another, just like you do with the four-finger horizontal swipe gesture on the iPad. It’ll make switching between your email client and your browser, or your text editor and your notes app, require much less effort than it does now.

Sounds simple, right? What could be a better, more natural implementation than that?

Well, the truth is, Apple’s almost certainly considered this mode; and Arya himself hits upon the most obvious reason why it’s been passed by:

Like the multitasking gestures on the iPad, these new gestures will be in conflict with several third-party apps, which already use edge-based gestures for some of their features.

Additionally, several of Apple’s own apps–like Safari and Maps–register edge-based input as normally-tracked motion across the touchscreen. In practice, this allows users to hold the device and slide their fingers and thumbs into various input zones without being forced to lift and move their digits each and every time. Eliminating this natural behavior and replacing it with drastic system-level actions (like switching apps) would yield far too high a rate of accidental input for Apple’s refined UX tastes.

That alone is enough to block Apple’s adoption of the feature, and–until the Home key itself is redesigned and/or made capacitive–we probably won’t see any significant change to the current system.