you can get shemaghs (arab scarves) on ebay or at urbanoutfitters (.co.uk if there isn't one near you). no idea of a trendy but unpopular scarf i'm afraid...
It might sound daft, but you could try charity shops and womens clothes shops. If you're after something individual and different, you're not going to find it on the high street, especially as regards mens' scarves. Buy something you like no matter what others think, it's all in the way you wear it :-)