There are fascinating Mac rumors afoot these days, topped with the report that Apple’s next reference operating system release may arrive sooner than expected, perhaps as early as the first quarter of next year.

The claim is based on a slide presentation delivered at a San Diego conference last week that featured Apple’s director of Unix technology, Jordan Hubbard. In listing the release dates for various versions of Mac OS X, 10.6 was apparently slated for “Q1 2009.”

If confirmed as something other than a typo (meaning someone meant to indicate Q2 or Q3), an actual release date might even be announced during the expected Steve Jobs keynote address at Macworld in January 2009.

Officially, Apple is quoted as saying they have nothing new to announce. That, of course, isn’t necessarily a denial, so they are, in effect, allowing the revelation in that slide to continue to stoke the fires of speculation. Indeed, this is the marketing approach Apple may well have taken from time to time to build demand for a new product.

On occasion, for example, you’ll hear a story about a page describing a new Mac appearing briefly at Apple’s site. Just before the word gets out, the information disappears. Oh well, maybe it was a nothing more than a screw-up on the part of a Web programmer who was subsequently chewed out by his immediate supervisor or even Steve Jobs himself.

Or maybe, just maybe, it was all part of the plan. With no proof of its existence, other than a few screen shots, the errant page might even be a mockup someone did in Photoshop. Certainly Apple will never admit to anything and will go on to repeat its mantra that they “don’t comment about unreleased products.”

This isn’t to say Apple hasn’t been dropping more and more hints about its product plans of late. When the iPod lineup was refreshed in September, the invitation that the press received made it quite clear what the fuss was all about. Apple made no secret that it’s October briefing was all about note-books, which didn’t stop some from suggesting that new iMacs were going to be part of the agenda.

More recently, Apple has conceded there will be no more new product introductions this year, which is the same as telling everyone in these difficult economic times that if you have enough money to buy their stuff, do it now. Don’t wait for an upgrade, because that won’t happen until 2009. Maybe that is a small part of the reason why Apple appears to be doing so well in terms of reports surveying recent Mac and iPhone sales.

You see, it’s generally believed that premature revelations about something new and different will do nothing but gut sales of existing versions of a product. But there are times when it’s totally appropriate to start a buzz, such as the announcement of the original iPhone six months before it actually went on sale.

With Snow Leopard, it’s not as significant a matter as, say, Leopard before it. That’s because Apple has already diminished your expectations by admitting there will be few new features. Instead, 10.6 will be designed to clean up the plumbing and make it more business friendly. The latter will arrive in the form of enhanced Microsoft Exchange support for Mail, Address Book and iCal. You won’t even see it unless you need it, and most of you probably have no use for Exchange, unless it’s required at your office.

Improving support for Macs with multicore processors, offloading tasks to the graphics processor, and such additional system enhancements as expanded 64-bit support won’t mean much unless you are a programmer. Or you do the sort of work where every increment of additional performance is significant.

That’s one of the reasons why my doubts are growing that Apple actually intends to charge its standard $129 upgrade fee for Snow Leopard. You see, personal computer users have been conditioned to expect a bevy of new features to accompany a paid software upgrade.

Surely that fuel’s Microsoft’s business plan. They earn a lion’s share of their income from software upgrades, and they have to do what they can to entice you to abandon the old version. Well, maybe Windows 7 will be a lesser release, although Microsoft is still touting new interface eye candy and support for Multi-Touch.

It’s also possible that Apple will relent and meld some nifty new features into Snow Leopard. Indeed, just clearing out Leopard’s notorious rough edges with iCal and Spotlight might be sufficient to satisfy some of you. There are also unconfirmed stories that the controversial and endlessly buggy Mac OS X Finder is being rewritten in Apple’s Cocoa programming language. Maybe so, but that’s not something that would necessarily change its look or feel.

Regardless of when 10.6 appears — whether in the first quarter or a few months later — I expect that Apple will charge a modest upgrade fee, say $59 or so, or just give it away to all you loyal Mac users. Well, at least those who have Intel-based Macs, since it’s doubtful Snow Leopard will support the PowerPC.