If Nintendo doesn't reveal any new information about Wii U at GDC, I wonder what Reggie was referring to when he in interviews with CNN and GameTrailer at CES said they would share more information between then and E3. It's unlikely however that they won't bring any news to GDC, seeing the wonderful opportunities they are being given.
If we look at the roadmap of industry events Nintendo is attending, this is the rundown (of more prominent events anyway):
WonderCon
16th of March 2012 - 18th of March 2012
This show (which is connected to Comic-Con International) is mostly for comic books, major Hollywood movie studios and stars of comics, movies, and television. But there is a department for gaming as well. Last year 3DS was featured there in several ways. Exhibiting game companies include Nintendo, Capcom and Namco Bandai. This is a potential place for news.
http://comic-con.org/wc/
MCM Expo Birmingham
31st of March 2012 - 1st of April 2012
Nintendo itself isn't exhibiting here, but they sponsor the event, and there is usually much Nintendo merchandise (comic books, plush dolls etc.) for sale. Not expecting anything here.
http://www.birminghamcomiccon.com/
PAX East 2012
6th of April 2012 - 8th of April 2012
While exhibitors and sponsors are yet to be announced, it is extremely likely for Nintendo to exhibit here. Last year they had a fairly large booth where several games for 3DS were available for play, including Pokémon Black/White, Steel Diver and The Legend of Zelda: Ocarina of Time 3D. Many other gaming companies exhibit here as well, many of Nintendo's partners. A likely spot for news.
MCV Industry Excellence Awards 2012
19th of April 2012
This is an award show where new games aren't normally revealed, so I doubt we'll hear anything here. Nintendo (UK branch of Nintendo of Europe GmbH I suppose) has qualified as finalists in these categories: Games Publisher, Marketing Team, PR Team, Sales Team, Trade Marketing Team.
http://www.mcvawards.com/
MCM Expo Londo
25th of May 2012 - 27th of May 2012
This is the same format as the Birmingham event, but much bigger. And here we see multiple game companies, including Nintendo, Capcom, Microsoft, Tecmo Koei, Warner Bros. Interactive and more. For example, Nintendo showcased Xenoblade Chronicles last year at the event. Here I can see some kind of revelation regarding Wii U, though the chances are slim.
http://www.londonexpo.com/
I may have forgotten some events, but the above is what I have found listed. If you know of any more event Nintendo is attending, gimme a shout.
Now, they could of course distribute more information in a press release, just like they did when the Wii name was revealed on April 27th, 2006. I think however a simple press release wouldn't be enough. A theme site perhaps where new features are explained through articles, images and videos could be something. I doubt Nintendo wants to submit information in a surreptitious way after the confused turmoil that arose in conjunction with their media briefing at E3 2011. An inscrutable reveal of let's say a GPU based on ATI FirePro V9800 (this will never happen, it's just an example) would probably incite us readers of NeoGAF, but the mass market and the casual gamers would probably be disgruntled.