With just one week left until Samsung reveals the Galaxy S4 at its Unpacked event on March 14, mock-ups and teaser screen shots for the next-gen S4 continue to pop up all over the Web. Even possible cases for the S4 have surfaced at CeBIT 2013, which is currently taking place in Hanover, Germany.

While not a go-to convention for huge mobile-related announcements, CeBIT often offers just the right sneak peeks to give more insight into upcoming gadgets to excite enthusiasts even more, according to Android Authority. In this case, purported hard cases for the Galaxy S4 made in China were spotted in the wild at CeBIT 2013.

Mobile Geeks got a chance to compare the cases to one for the Samsung Galaxy S3 and also had a Galaxy S3 device on hand. The hard case is the newest proposed Galaxy S4 accessory, while the others are previously known cases that hit the market in February from online retailers like MobileFun.

While the presenter noted that the S4 and S3 cases were similar in that the openings for the speaker, camera and flash were all on the back, the openings on the S3 case went from left to right speaker, flash and camera, and on the S4 case, it went flash, camera and speaker.

The presenter also noted that one of the S4 cases features a double opening where the speaker may be, while the other two had quite large openings, possibly suggesting that there is something going on with the speaker on the Galaxy S4, perhaps a larger speaker or more than one.

In addition, the Galaxy s4 hard case in comparison to that of the Galaxy S3 is longer height-wise, suggesting a thicker phone. It is also longer width-wise than the S3 but slightly shorter length-wise. The case is also much more rectangular in shape, more resembling the Galaxy S2, than the curved corners on the Galaxy S3 -- something that has been discussed heavily in rumors.

Android Authority notes that the appearance of this hard case at CeBIT is no confirmation that it belongs to the Galaxy S4.

Chinese companies are infamous for producing various accessories well before their corresponding devices are even on the market, relying on floating spec rumors or possibly having acquired tips from insiders. Other phones have seen similar accessory controversy, such as the images of the iPhone 5 cases that were floated around Web prior to the release of the iPhone 4S.

Online retailer CellJewel introduced a case for the Galaxy S4 in February that has been dismissed as a mock-up, as the curved edges failed to keep in step with currently accepted rumors. Later, MobileFun released its rectangular-shaped cases -- with the double speaker opening -- that many suggest is more plausible for the Galaxy S4.

As Samsung is keeping a particularly tight rein on the actual details of the Galaxy S4, as suggested by its recently released teaser trailer in which the smartphone remains in an especially tantalizing box. We will likely just have to wait to see what goes down at New York City's Radio City Music Hall on March 14.