Andy KB1OIQ has posted a file on the [BITX20] IO Group files page: kb1oiq_i2c_mod.pdf that describes the hardware and software modifications that he performed on his uBITX to free up digital pins on his arduino. You will need to be logged in to the Group page to access the file.
Andy converts the LCD to use the I2C bus, thus freeing 6 Arduino digital pins for other uses. Only very minor modifications are required to the Raduino sketch (and you will need to install a different library). He documents every step involved with photos. Well done!
[EDITOR Comment – removal of the two pull-up resistors on the additional board and direct connection to the I2C A4 and A5 ardunio pins should suffice without use of a level converter board. However, the cost of adding in the level converter is negligible and will work well!]