It seems increasingly likely that Apple is going to retire the 30-pin dock connector that's been present on every iPhone since its debut -- along with millions of iPods and iPads -- with a slimmer and more modern connector .

While we have no hard evidence relating to the redesigned connector itself, hardware leaks from multiple sources of what is claimed to be the metal chassis for the upcoming iPhone 5 show a radically smaller dock connector hole on the bottom of the device.

Given the weight of the evidence, I'm now almost certain that a new dock connector is incoming. If nothing else, the existing connector is almost a decade old and a significant number of its 30 pins are legacy .

Talk of a redesigned dock connector has led to more talk that this time around Apple will take the redesigned iPhone 5 dock connector and slap it into all of its iOS devices by the end of the year, including a new iPod nano, iPod touch, the 9.7-inch iPad and the much-rumored but as yet mythical 7-inch iPad Mini .

It would certainly simplify things for Apple, consumers and Apple's hardware partners if all iDevices shared a single unified connector, as it would reduce the fragmentation caused by the legacy 30-pin dock and the new dock connector. However, it's rather ambitious to suggest that Apple could pull this off in one fell swoop by the end of the year.

After all, there's a small matter of supply chain.

Apple has staggered the release of new iPhones and iPads, and for good reason. Launching such enormously popular devices puts an absurd strain on the entire component supply chain. Screens and Li-ion batteries in particular are a limiting factor, but so is NAND flash and Silicon-on-a-Chip (SoC) processors.

On top of the supply chain, there's manufacturing issues to take into consideration.

The iPhone 5 launch alone is likely to be massive. During the quarter following the release of the iPhone 4S Apple sold a record 37 million iPhones. Even the iPad 2, which by then had been out for months, saw record sales of over 15 million units over the three-month period.

Releasing a new iPhone, iPad and an iPad Mini over what remains of 2012 would put an enormous pressure on Apple at a time that it can ill afford to have supply chain issues -- the highly profitable holiday period.

The last thing Apple wants is shortages and delays at this crucial sales period.

My bet -- based not only on past history but what I'm hearing from the supply chain -- is that Apple will stick to the existing release timetable. We'll likely see an iPhone announcement -- where we will also see new iPods announced -- come September or October , and this will be followed by an iPad announcement early next year.

As to the speculative 7-inch iPad Mini , it might make sense for Apple to get this out of the door by the holidays, especially if the Cupertino giant wanted to take some of the wind out of the sails of Amazon's Kindle Fire -- possibly the Kindle Fire 2 by then -- and Google's Nexus 7 tablets.

That said, given that iPad sales are still incredibly strong, the introduction of a newer, smaller, and cheaper model could cannibalize sales of the higher-priced, higher-margin 9.7-inch iPad during a period where Apple is likely to sell millions of iPads. It might be better for Apple to wait until next year and release the iPad 4 and iPad Mini together.

Also, let's bear in mind that Apple not only sells the iPhone 4S and iPad 3, but also the older iPhone 3GS and iPhone 4, and the iPad 2. Are these older, lower-priced devices going to get new dock connectors too?

Revamping the entire iOS line by the end of the year would represent the largest hardware restructure carried out by any consumer electronics manufacturer in history.

It's also worth pointing out that even if Apple did revamp the entire iOS lineup, fitting the new dock connector all round, it doesn’t solve everything. Apple has sold hundreds of millions of devices featuring the 30-pin dock connector .

Only time is going to make them go away. It's going to be years before the 30-pin dock connector is gone for good.

Image source: ETradeSupply, Nickolay Lamm/InventHelp.