mishmash, flimflam, spick and span, mix and match, riffraff, knickknack, kitty-cat, pitter-patter, fiddle-faddle, this and that, snicker-snack,
ship-shape,
flip-flop, hip-hop, clip-clop, ding-dong, sing-song, King Kong, ping pong, tick tock, wishy-washy,
big bad wolf (as opposed to good little lamb, this classic example shows the rule surpassing usual adjective order).
Arguable examples:
slippery slope,
sick and wrong, sticks and stones, skin and bones, big and strong, prim and proper
big strong noun (as opposed to weak little noun),
spindash or spin-dash, not dashspin or dash-spin.
