Not really. But you can take a look at Maltron keyboards, which are non-staggered and also curved. From what I can find on the web it seems that they have done some research.
The [Kinesis](http://www.kinesis-ergo.com/) Advantage is a cheaper alternative to Maltron that follows the same design pattern. It's the keyboard I use, and it's definitely more comfortable than a typical staggered keyboard, or even a simpler ergonomic keyboard.