My life size R2-D2 replica exhaustive build log is hosted on the Astromech.net forum, which is the site run by the R2 Builders Club. I have also developed various parts and electronic systems and then made them available to the club. The MarcDuino automation system is probably the most famous of them. Reference information about these various systems is hosted here.
The source of it all. This will take you to my detailed build log, from start to finish. You will need to sign up for Astromech.net membership to view the blog (it's free).
This is the iPhone app that goes with the MarcDuino boards and allows you to play sounds and remote control the dome and gadgets.
(Note: there is also an Android R2 Touch app not build by myself, but developed with my blessing. It is not supported by me, but by Astromech member KG 204, more details here)
Very bright holo lights that you can build yourself or order. They will fit perfectly in your holoprojectors. They are primarily meant to be triggered by the MarcDuino boards, but can be hooked to any other system - or a switch.
A "2-3-2" Droid is one that can switch from standing straight up on it's two outer feet with the central foot retracted in the body (the "2" position), to a rolling stance with the center foot extended in front (the "3" position). All without face planting during the transition...