So here are a handful of details we’ve heard from a couple of solid sources regarding the fourth-generation iPod touch, which we believe to be accurate:

* The Sleep/Wake button has shifted from the top left of the device over to the top right, mimicing its placement on the iPhone family.

* The camera is below the Sleep/Wake button, with a microphone pinhole off to its right.

* Volume buttons appear to be separate from one another rather than one piece, but stay in the same general position as in the second- and third-generation iPod touch models, as do the Dock Connector port and headphone port on bottom.

* It is slightly thinner than the second- and third-generation iPod touch. The rear casing has corner and side radiuses that are, as we previously noted, MacBook Pro lid-like, and the center does not bulge, so it can rest flat on a table like the first-generation iPod touch. What used to be a soft curve of the rear shell that wrapped around to surround the front glass is gone.

Here is some stuff that we’ve been hearing but not posting over the last week because it has remained really sketchy—note that we are not making any claims as to its accuracy .

* Claim: Apple wants to give the iPod touch an optional 3G cellular data feature and has readied a second version with a micro SIM slot like the iPad with Wi-Fi + 3G. According to a new and untested source, who is mirroring speculation we’ve heard from others, Apple wants to make the iPod touch an iPhone without cellular voice service.

* Claim: Apple is giving the iPod touch a built-in VoIP phone application for both voice and FaceTime video calling. We received screenshots purporting to show the iPod touch “Phone” application and its settings features, running on a Retina Display no less, but they appeared to have been Photoshopped, and a number of little details led us to question the claims. While Apple’s plans to add FaceTime software, a microphone, and camera to the iPod touch 4G are locks at this point, and iOS 4’s background support for VoIP makes this feature entirely possible in any device running the OS, it would be exceptionally bold for the company to offer a full-fledged Phone application—complete with Voicemail, Call Forwarding, and Call Waiting—as a bonus for iPod touch users.

 

But Apple has known to be bold. And what would look like a slap in the face to cellular voice providers really would be offset by customers’ new demands for cellular data plans, plus VoIP’s roughly 1.3MB per minute data drain on whatever cellular data plan you pick. Common limited 250MB data plans would offer under 200 minutes of calling per month, with around 1500 minutes for a 2GB plan, assuming you did nothing else with the services. Video calling with FaceTime—assuming it was allowed over a given 3G network—would eat four or five times as much data. The aforementioned untested source claims Apple will host the VoIP servers, an extension of the matchmaking servers it’s already using for FaceTime.

The images above are some of the ones we received and, as noted, are of questionable veracity. In any case, we’ll know more this afternoon.