The new Kinetis SDK 1.0 Beta supports building and debugging on Linux systems. I just got it to build on mine. Just required a very simple modification to a single file to tell it where my gcc compiler is located.
I am using Ubuntu 12.04 LTS with arm gcc 4.7.4 installed to /usr/arm-none-eabi/
In the KSDK folder /mk/, edit the file common.mk file.
ensure this section is un-commented, and change the path to the appropriate path where arm-none-eabi is installed on your machine. For me it is /usr/
GCC_TOOLCHAIN_DIR := /usr
CC_VERSION := 4.7.4
now cd into the directory of the app you want to build
mac@mac-VirtualBox:$ cd ../apps/hello_world/gcc/frdmk64f120m/