Single-sided board developed in KiCAD. Instead of more expensive FT232/AT90USB I used cheap (1.5$) CP2102. Additional connectors for RS232 and I2C (XP2/XP3):
Files: ul_arduino_uno-01.tgz
Project blog post: http://electrotormentor.blogspot.com/2011/06/single-sided-arduino-uno-board.html
I2C modules will be published here: Електроментор: i2c