That's very interesting. Adding a couple buckets to this should work. Is there a way to specify knowing the duration of the tracks returned? Tracks are often multiple for a given song - without knowing the duration (ie. preview).
http://developer.echonest.com/api/v4/playlist/static?api_key=XXX&type=genre-radio&genre=abstract%20hip%20hop&genre_preset=core-best&bucket=id:deezer&bucket=tracks&limit=true