Given that the MBPs etc were only recently upgraded to Core Duo 2's I really dont think there will be an across the board upgrade. It would make an extremely expensive laptop, cripplingly expensive given Apple's pricing policy!
Expensive compared with a cheap crappy laptop, but compared with similar spec'ed Dell or anyone else actually not more expensive ... but cheaper.
ZDNet's Ed Burnette priced out a Dell XPS M1710 versus the Apple 17-inch MacBook Pro. After matching the following components, the Apple MacBook came out on top, shipping for $2,699 before taxes versus the Dell's $3,222 price tag:
Intel® Core 2 Duo T7600 (2.33GHz, 4MB L2 Cache, 667 MHz FSB) processor, 17-inch wide screen display, 256MB dedicated 3D graphics card, 2GB DDR2 SDRAM at 667MHZ (2 DIMM), 100GB 7200rpm SATA Hard Drive, CD/DVD Burner (DVD+/-RW), Integrated Audio, Standard battery, Internal Bluetooth (2.0 + Enhanced Data Rate), Internal 802.11g wireless, DVD and movie editing software, 1Yr Ltd Warranty, and Customer support (at least 30 days).
The Dell offered a higher screen resolution but the Apple has the built-in iSight (webcam) and back-lit keyboard.