The iPhone display has maintained the same 3.5-inch size since its debut in 2007, but as anticipation builds up ahead of this year's expected iPhone 5 launch, so do expectations of a larger screen.

Over the past year, we've witnessed a trend of larger smartphone displays, increasing from about 3.2/2.5 inches to 4.5/4.65 inches, or even as high as the 5.3-inch screen the Samsung Galaxy Note boasts. The next-generation iPhone is rumored to launch in June or later in the fall, and is expected to feature a larger display as well - at least 4 inches. While many just dream of it, others tried to actually envision a larger screen, and came up with interesting mock-ups of how it would work.

The Verge, for instance, details a very promising solution for making the screen bigger without altering the external form factor of the device, while also maintaining the retina quality of 300+ pixels-per-inch (ppi).

The Verge describes how last week, a Vergecast caller named Timothy Collins shared his opinion on how Apple could achieve this. All iPhones have featured a 3.5-inch display with 3:2 aspect ratio, and Apple offered a 960 x 640 resolution since the iPhone 4. If Apple were to increase its diagonal size, 4 inches would be the optimal size according to The Verge. Consequently, the solution seems to be keeping the same 960 x 640 resolution, while increasing the pixel size. However, this would dramatically reduce the pixel density to 228 ppi, well below Apple's 300+ ppi retina quality standards. This is where the Verge reader scores extra points with his idea.

To avoid reducing pixel density, Timothy Collins came up with another solution: change the aspect ratio. Collins' idea was to leave the shorter side of the iPhone screen unchanged, meaning 640 pixels at 1.94 inches, and increase the longer side to 1152 pixels and 3.49 inches, leaving a diagonal of roughly 3.99 inches. The Verge further explains that 1152 x 640 means an aspect ratio of 9:5, and the extra 192 pixels along the longer side would allow for an extra row of app icons to be included on the home screen.

Many AppStore apps utilize standard iOS UI elements, which typically involve a title/navigation bar at the top and a tab/menu bar at the bottom, with the main content displayed in the center. With this in mind, The Verge suggests Apple's sixth-generation mobile OS could auto-detect standard UI-based apps and arrange the interface accordingly. On the other hand, apps that are not built with the standard UI elements would require help from developers to utilize the extra pixels and work on the 9:5 display.

The Verge further details how wide-screen videos could be played better, without the current 940 x 50 black margins at the top and bottom of the screen when viewed in landscape mode.

In response to the amazing mock-up The Verge has presented, a 9to5Mac reader, Spencer Caldwell, came up with his own mock-up to support a 4-inch screen. Spencer Caldwell took Timothy Collins' idea and added more pixels vertically, while keeping the same pixels horizontally, similar to the iPhone 4S configuration of 640 x 1152 pixels. In addition, the 9to5Mac reader ditched the circular home button on the iPhone by implementing last summer's Photo Stream leak into the mock-up device. On a larger iPhone, an extended home button might indeed look better.

Still, the only feature that can be confirmed at this time is that the next-generation iPhone will be a 4G LTE device. None of the other rumored specs and features has been confirmed, but these mock-ups do suggest the iPhone 5 could be amazing.

Start the slideshow to check out the amazing mockups of iPhone 5 with 4-inch screen.

(reported by Alexandra Burlacu, edited by Surojit Chatterjee)