Thank you! The /proc/config.gz was exactly what I was looking for! I was not able to configure it with menuconfig though (I think that needs intermediary config files), so I just used oldconfig instead.
I used CodeSourcery from a Ubuntu host and everything worked perfect for me. But I did not try 'make modules', I just ran 'make ARC=arm CROSS_COMPILE=arm-linux-'. CodeSourcery is the only ARM target compiler I have installed.