Ah! Here we go! Actually, it was Brighthand's Overview of Windows Mobile 2003 Second Edition, available here:
http://www.brighthand.com/article/Ov...Mobile_2003_SE
Read the "VGA Screens" section. Brighthand mentions 240x240 and 480x480
(not 120x120, stupid me), but there is no mention of 320x320. Which makes sense, for the same reason Palm OS uses 320x320: legacy factors. All Pocket PC/WinCE apps to date have assumed a 240pixel-wide screen, just as all Palm apps assumed a 160pixel-wide screen until Sony's Palm OS 3.5.
This is also why I would discount any rumors of a PalmOne Treo 650 running Windows Mobile. PalmOne cannot to reengineer the Treo with a different screen because it simply can't afford to. PalmOne only designs devices and sells them; it outsources manufacturing to third parties. It would cost them a lot of money and time to reengineer the 650 now, not to mention changing manufacturing contracts. Also not to mention the support headaches of having a device with 2 different screens, and 2 different OSes. I cannot believe this is PalmOne's strategy.