Well Google Chrome is on its way... but not sure how that will hold up being browser based...
I've been following Google's SW strategies, but I am not a Google insider. Everything I'm spouting here should be read as if I'm prefacing it with: "I think," "I'm guessing," or "ahem... I have a theory."
Simply put, ChromeOS is the non-web platform for Google apps. When ChromeOS can connect to google.com or alternative server it can use it for centralized authentication/profile serving and document storage. What the Google servers do is handled locally by Google Gears when offline or when info is most sensitive.
Components: Linux kernel, ChromeOS, Chrome browser, Google apps, Google Gears, (Google servers), ...
Apps - mail, messaging, word processing, spreadsheet, presentation, calendar, authoring, ...
Chrome - rendering, menus, forms, encryption, certification, desktop, ...
Gears - database, document storage, authentication, profile database, java, http. ...
Linux - bios, boot, scheduler, processes, threads, file systems, networking, ...
So what does ChromeOS need to bring to the table? graphics library, mathlib, rpc, ...
They could make a clean break from cross-platform functionality and legacy usage models by leaving out rpc. I'm wondering if they'll make use of GNU libraries, Xlib, OpenGL, ... but I think they'd go for a lighter-weight solution.
"Google Legacy Emulation" could be a follow-on product to run WoW, MAME, Mathematica, ...