as already said above
stripes would be retro traditional, but interesting
if You use any brownish or yellowish colours, nothing with greenish shades, all warm colours (so no Khaki)
blue and blueish black also goes
indigo, purple and green would be rather expensive dyes (for arab tribesmen), so only for characters or in small amounts (but could go as a trademark or unit colour)
looking forward to see Your "alternative arab bandits"