Rumors of an ultraportable MacBook Pro are nothing new [1] (in fact, they're pretty old, as far as Apple rumors go) but the latest tidbit seems a bit more credible than most. AppleInsider is reporting that the mythical sub-notebook will finally show its face at the MacWorld Expo in mid-January, following months of development. Here's what they're telling us to expect in terms of specs:

• No optical drive
• A weight of 3.4 pounds with battery--half as heavy as the 15" MBP
• NAND Flash SSD in lieu of a mechanical hard drive
• "[N]ear instantaneous boot times," thanks to the SSD
• 13-inch, LED-backlit LCD panel

Those are some pretty serious specs and could end up pushing this little lappie's price tag north of $2000. Still, if you're looking to buy the thinnest, lightest Mac ever produced, money probably isn't much of an issue. MacWorld is scheduled to run from January 15th to 18th, so I suppose we'll all have to wait until then to find out if there's any truth to this one.

For more on the rumor:
- see this Apple Insider article [2]