Two stories...
One of my competitors has their site redesigned about once a year. Twice in the past three years their designer tossed the new site up with noindex on every page.
We notice right away but it usually takes them a week or two to figure out what's happened. When the remove the noindex the site returns to normal in a few days.
I noindexed a folder of 80 thin content pages immediately after Panda 2.0 in April, 2011. I allowed the pages to be open to visitors because they had some good photos and data tables on them. The site escaped in the Panda 2.1 about a month later. 
Then, I started publishing same-topic articles on the same URLs, using all of the original content that was noindexed. When the article is finished, I remove the noindex. A new articles has the noindex removed about once a month. (It takes a long time to republish 80 pages at the rate of one a month.)
These URLs reside two clicks from the homepage on a long-established and reasonably powerful site. When I remove the noindex the amount of time for the page to start ranking can vary from hours to several weeks. A few times I went into the code to see if I forgot to remove the noindex - and I had not forgotten. Some of these page go right to the top of google for competitive terms. Others have trouble getting reindexed even though we point internal links to them on many parts of the site. We have waited a couple of months for some to be reindexed.
Good luck.