IDEO is actually very famous in the product design world. You've probably used more IDEO-designed products than you realize. They are a case study (literally) in creating a creative-productive work culture.

Unknown to you maybe - but IDEO is probably more well known than 37signals. They probably designed something within your reach right now http://en.wikipedia.org/wiki/IDEO

IDEO is one of the most successful design firms in the world.

For reference, check out this book by Bill Moggridge, a founder of IDEO.

http://www.designinginteractions.com/book