So far we've mostly been targeting iOS and Android for tablets, but there's another interesting tablet OS coming down the line -- Windows 8, which will run on both conventional PCs and tablets.
I've been looking into what it would take to support a Windows 8 Metro style app well, and have written up some notes and screenshots:
A standalone test application that runs on Windows 8 Consumer Preview and implements some of the system integration (but none of the article reading!) is on my github account:
There's also a preliminary solution & project file in the main app's git repo, in the WikipediaMetro subdirectory, but this doesn't fully run right now (the way we load some scripts violates a security rule) and doesn't do any of the integration. I'll try and get it running proper soon...