Anticipation of Apple's Tuesday unveiling of the iPhone 5 has reached fever pitch, with speculation on everything from form to features running rampant. Chinese state-run carrier China Unicom added to the frenzy this week at the Macworld Asia expo in Beijing during a slideshow that included a segment documenting the evolution of the iPhone. The slide, which is available on Japanese tech news site PC Watch, includes a section for the as-yet-unreleased iPhone 5, which clearly indicates that the new phone will implement HSPA+ for download speeds of up to 21 Mbps.

If true, this would mean the download speed of the new iPhone would be nearly three times the current generation's 7.2 Mbps.

It's a heady prospect for iPhone customers, who have been wondering about Apple's next move vis-à-vis network speed. The fastest network currently available is 3GPP LTE - also known as 4G LTE - which offers a theoretical download speed of over 100 Mbps. However, Apple CEO Tim Cook has stated that the company will not be pursuing 4G LTE compatibility because the technology requires too much physical real estate and is an excessive drain on battery life.

If the iPhone 5 were to adopt HSPA+, it would mean access to a theoretical download speed of 84 Mbps for iPhone users. While short of speeds offered by LTE, the benefit of faster download times would be amplified by an even slimmer profile, which is another feature Apple is rumored to be presenting Tuesday. Case makers have reportedly been leaking photos of iPhone 5 cases that are built for devices longer and wider than the iPhone 4. Though Mashable, reporting on the topic, cautions against placing too much stock in pre-release models of cases, which are often prototypes based on guesses for potential specs, many case manufacturers do seem to be anticipating a thinner, wider model. In September, BGR reported on images published on Case-Mate's page of iPhone 5 cases that indicated that the new device will have a slim profile and rounded edges, a la the iPhone 3 and iPad.

Case-Mate subsequently removed the images and page, publishing in its stead a placeholder page reading We'll have your cases when you have your new iPhone and an email form for customers who want to be notified when the products are available.

With the months of speculation soon drawing to a close, customers await Tuesday's event with what seems to be an anticipation bordering on certainty of yet another hit from Apple. The only real question that remains is whether the iPhone 5 will still have any real surprises up its sleeve by then.