Here are the lines which you can play with.
These are the originals. You can copy them to the Blanco css or your own theme.

https://dl.dropbox.com/u/40680080/key-size.txt

For example, if you want the keyboard area remains the same size:
Change key-height-*.*: 60px; to 70px, also change key-margin-bottom: 18px; to 8px (+/-10)