Here are 2 DIYs related to fitting an airbag wheel, but I don't think they address the horn. I have a friend that has a wheel & airbag like the upper one in your first picture, reasonably priced, if you end up needing one.
http://www.frankies-bmw.com/3series/...ring_wheel.php http://www.dvatp.com/bmw/diy/steering_wheel_conversion/