Mac fans around the world are anxiously awaiting next week’s big announcement from Apple.  Those fanboys among us are eagerly looking forward to seeing a healthy Steve Jobs finally descend from Mt. Cupertino to deliver the fabled MacTablet/iSlate to the masses.

One of the qualities that makes Apple somewhat unique in the technology landscape is that they’re not very keen on vaporware. I can’t remember the last time Apple announced a new product without committing to a rock solid delivery date. When introducing the first generation iPhone a few years ago, consumers could pre-order the phone the day it was announced and could expect delivery the same day the product became available on store shelves.

In the eyes of Apple, this is more than an expectation. It’s a promise. Imagine for a moment that next week Apple announces the new iTablet and tells the world that they can expect to lay their grubby little paws on the device promptly at 9AM on April 1, 2010. Now imagine that just a few weeks prior to the anticipated ship date, they say, “oops, we were just a bit off in our estimates. Turns out it won’t actually ship until April 15^th.”

How many hundreds of millions of dollars do you think would be shaved off their market cap? While the next few days will see endless speculation regarding which features this tablet/slate might or might not include, I can guarantee you one thing: it will ship when Apple says it will ship.

Few companies currently have as much at stake when it comes to calculating a project ship date as does Apple. And when so much is riding on estimating the delivery date for one of the technology industry’s most anticipated products, how do you go about picking a ship date with 100% confidence?

Obviously, I have no insight into how Apple manages their project plans but I think it’s a safe assumption that their product managers rely heavily on project buffers. These cushions of time provide teams with a measure of consolation when they don’t have a firm grasp on how long a given task might take (especially true when it comes to tasks that have no precedence). When bringing an entirely new innovation to market, you can imagine a project plan that is overloaded with such buffers. But because these buffers are really nothing more than arbitrary chunks of time, they only account for one side of the exit date equation (i.e., the worst case).

So yes, with enough project buffers you can set a promise date with a reasonable amount of certainty. But by overloading a project plan with buffers, you end up with a schedule that is stiff and unable to respond to market dynamics. This is one of the hidden benefits of incorporating ranged estimates into project planning. By accounting for both the best- and worst-case scenarios – which is especially powerful across an entire portfolio of projects – you can realize the best of both worlds while setting realistic promise dates.

On what date do you think the MacTablet will ship? Leave your best guess in the comments and we’ll give the winner (the first to post the correct date or the closest to the correct date) a $25 iTunes gift card.