Harry Murray uses the term "strymph" for flies that can be fished either as streamer or as a nymph (sometimes on the same cast). He ties something similar to what you describe where he uses a bunch of shank length ostrich herl for the tail. http://catalog.murraysflyshop.com/co...urrays-strymph

Rich Osthoff ties a similar fly with a long tuft of rabbit fur for a tail. He advocates fishing it in an "active" manner which strikes me as a cross between dead drift nymphing and active, tight line streamer fishing. http://www.richosthoff.com/2378.html