So far, I've made:

• dc servo modules
• stepper motor modules
• Canon EF lens modules
• RGB LED modules
• RC servo modules

Plus a server that lets you playback motions on whatever you've got connected at the time... but this is just Part 1. Stay tuned

Half the info you need is in the blog post, the other half is in the comments below. The only trouble I had was iris control, which I couldn't get to work on the cheapest Canon kit lenses (though my better lenses all responded fine):

https://pickandplace.wordpress.com/2011/10/05/canon-ef-s-protocol-and-electronic-follow-focus/