Although the iPad 2 hasn't yet arrived (or even been officially revealed by Apple), speculation is mounting regarding the iPad 3 release date after pundit John Gruber suggested on his blog that HP's 'summer' TouchPad release might coincide with Apple's tablet update-after-next.

"If my theory is right, they're not only going to be months behind the iPad 2, but if they slip until late summer, they might bump up against the release of the iPad 3," he wrote.

In subsequent posts, Gruber elaborates on his thinking, saying the iPad's annual release moving to September would enable Apple to replace the autumn iTunes/iPod announcement (which he considers "old news") and that it would scupper rumours during the holiday season that people should hold fire for an updated model. "Shipping new hardware in April adds another milestone to the iOS release schedule, too," he adds.

The problem with this thinking is that it's a very US-centric viewpoint and a shift to September would essentially force Apple to seriously ramp up inventory prior to launch.

With the original iPad, an April US release was subsequently followed by a limited release elsewhere (including the UK) a month later, with several more countries getting the device in July.

Initially, supplies were also seriously constrained. Move the refresh date six months and Apple has a problem if it follows the same pattern: a late September US release would likely lead to an October (or later) arrival in the UK, and December in other territories, with associated holiday season shortages.

Cannibalising iPad 2 sales

In addition, if the iPad 2 is rolled out in a similar manner to the original, Apple will be in the absurd position of rolling out the iPad 2 in the likes of Ireland and Mexico only a couple of months before the iPad 3 shows up in the US, which is a bigger recipe for hold-outs than the existing one.

Furthermore, there's also the question of sales spikes. An April release spikes sales relatively early in the year in the US, during a time of relatively quiet consumer activity, and in the summer elsewhere.

The holiday inevitably looks after itself. Move the iPad release much closer to the holidays and one can imagine a massive spike at the end of the year, but little to seriously drive iPad sales above their normal levels until the next refresh.

That's not to say Gruber is wrong. Refreshes to the iPad are likely being spread out over multiple revisions, so perhaps we'll see a FaceTime camera added in April and a Retina display at the end of the year, these quickfire updates ensuring Apple's tablet stays ahead of the competition.

But if this is the case, Apple will have to do a much better job of getting its hardware to countries outside of the US in a timely manner and figure out how to keep interest high after the glut of holiday sales is over.