The bed leveling seems to work pretty good, 9 grams servo connected on GND,+5V and D4. (PIN28)
Iam thinking of doing a seperate 5v supply, with an 7805 but right now all seems fine on the EXT header.
The Z endstop switch can be mounted on the servo arm. altough you may need thinner wire for not influencing the arm when positioning.
The STL for the servo mount can be found here: thingiverse.com/thing:252089
The firmware needs to be corrected to the dimensions of your own servo setup of course.
Modified Firmware:
dropbox.com/s/huxvmb8hsml5whh/MARLIN_2014-03-16_Pangu_i3_ABL.rar
I use Arduino 1.0.1 to compile, with the added hardware and library's for melzi & lcds.
dropbox.com/s/0ke7myxojt4i6ct/Arduinov101.rar
It is advisable to follow this guide to calibrate: soliforum.com/topic/4714/automatic-bed-leveling-and-z-offset-howto-level-23/
When complete, edit the Start G-code to do auto bed leveling in stead of 'normal' z calibration:
G28 X0 Y0 ;home X and Y
G29 ;probe bed
G90; set absolute coordinates
Please keep me posted on your updates!