A source has come forward with a new piece of information purporting that a forthcoming iPad revision will sport a thinner appearance and better sound, thanks to a redesigned speaker grill on the back panel apparently housing a wide-range speaker.

According to an unnamed Chinese source who spoke to Japanese webiste Mac Octakara, Apple’s iPad 2 should come in a 3 millimeter thinner enclosure, reportedly measuring 239mm by 186mm versus 242.8 mm by 189.7 mm for the current iPad.

It’ll allegedly sport a "wide-range speaker unit covered with metal mesh" as well. The news prompted the site to put together a mockup detailing what the improved speaker system might look like, included here for the sake of completeness. Other tidbits include an iPod touch-like back, in addition to the repositioning of the ambient light sensor to the top of the rear panel and away from the top of the display in the current-gen hardware.

The source also claimed the new iPad will boast the same 9.7-inch display as the original device. Apple will begin shipping iPad 2 in January, the source said in a contrast to the previous reports calling for an April launch and the initial output of six million units per month.

The news of a redesigned speaker system and thinner appearance comes on top of the swirling rumors predicting all sorts of enhancements, ranging from the camera on front and back to an SD card slot and even a USB 3.0 port.

Steve Jobs recently bashed seven-inch slates in a conference call with analysts, joking that these are only good if vendors ship them with sandpaper to sand your fingers down, hoping to put an end to the rumors of a smaller iPad in the works.

However, the comment only triggered a new round of speculation related to a smaller, seven-inch iPad – dubbed by the media the iPad mini – to be introduced alongside an improved 9.7-inch model.

The prospect of a smaller iPad has inspired Taiwanese celebrity Jimmy Lin to post an interesting photo of himself holding the original iPad in his left hand and what looks like a prototype seven-inch iPad unit in the other hand. Given Apple’s culture of secrecy, it remains to be seen if there is any substance to any of these rumors.

Source: Mac Otakara (original in Japanese, Google translation)