You might also look at a Matias Quiet Pro - they use custom switches based off old Alps designs (much more satisfying than Cherries, imo) and are a fair bit quieter out of the box: http://matias.ca/quietpro/
Blues are a different story. Personally, I can't even stand hearing myself type with blues, let alone someone else. If someone had the balls to bring one of those into an open office I would probably need noise cancelling headphones to work in the same space.
As others have mentioned, the noise from brown mechanical switches is from the plastic bottoming out and not the switches themselves. Therefore, some keyboards are de-facto louder than others.
My Das, for instance, is definitely more audible than my backlit gaming Max keyboard. Both use the same brown key switches, but the plastic & keyboard construction is different resulting in a more muted typing experience with the latter.
IOW, I don't think brown keys are unreasonable for shared work environments; they're not much louder than a standard Dell rubber-domed KB.
The blue switches in my DasKeyboard at home however... I think I'll have to upgrade just to get something a bit quieter.