That is pretty funny - had actually tried to put a bucktail 'wing' on the top side but couldn't get the look right since i had already built up too much thread. The mallard top-cover/'wing' sounds like a good idea, may have to try it on my next one. Had also had a thought of trying a softhackle wrap on it but never got around to it.
From the replies i got... i must be on the right track!
Thanks for the comments and ideas everyone.