I didn’t see this device in the supported list, but I though I would give it a shot.
Is the Luminary LM3S26xx or more precisely the LM3S2678 already supported by one of the existing Luminary/Cortex ports? If not, any plans to support this family?
There is only one Cortex-M3 port, which works with all Cortex-M3 devices be they from Luminary, ST, NXP, Atmel, or any other vendor. All you need to do is ensure the linker script is correct for your chosen device.