i think there's seven root filesystems in this 256 MB image (two JFFS2 and five SquashFS), and at least eight kernels (plus i think one kernel embedded inside of an FDT or something)
i've found Broadcom ARM, Cavium MIPS64, and Atheros MIPS32, all on Linux 2.6.30something
2.6.31, 2.6.32, 2.6.36