Rumors of Apple's upcoming "iPhone 5" have been surfacing for a while now, but firmer details were recently reported by GottaBeMobile in two separate exclusives, one of which may also add further credence to rumors of an iPad "mini" planned for the Christmas shopping period.

The site managed to get a hold of pictures of what appear to be engineering samples of both upcoming devices from trusted sources inside Apple's supply chain. The next iPhone would purportedly maintain the existing cosmetic design of the iPhone 4S but within a taller frame, further hinting at an increased display size.

According to the pictures, the phone measures 120mm tall x 58.6mm wide, and despite the taller frame it appears Apple is working hard to keep similar proportions to previous iPhone models, resisting the urge to follow in the same footsteps as Android smartphones now breaking the 5.0-inch barrier.

GottaBeMobile suggests the next-generation iPhone will have a 4.0-inch display, which is in line with earlier rumors. Around the back the camera layout appears to be the same as the current model and the engineering mock-up potentially adds credence to speculation surrounding the use of a metal rear cover alongside the more traditional materials Apple uses for the smartphone's chassis.

In a separate report GottaBeMobile posted photos and information that appears to backup recent rumors of a smaller iPad. The images depict what are believed to be early plastic mould samples, which the site speculates could be used to hone the production process as well as test accessories.

Closer inspection reveals that the alleged iPad mini would feature the smaller 19-pin dock connector that surfaced in earlier rumors surrounding the upcoming iPhone. It also appears that Apple will be using two speakers in the new iPad model, one on either side of the dock connector. By comparison the current model's speakers are on the reverse, which subsequently makes it easy to block them whilst holding the tablet.

The tablet is estimated to be around 213.36mm tall by 143.67mm wide, making it roughly two-thirds the size of the current iPad as well as thinner, bringing it in line with Google's Nexus 7 tablet. 

There are no noticeable features in the mock up to suggest the display size, but current speculation suggests it's around 7- or 8-inches in size, possibly using a Sharp IGZO (indium gallium zinc oxide) display which is capable of 330ppi - meaning we could see a retina display after all.

Both the new iPhone and iPad mini are rumored for launch at the same time in October.