Hi --
The following request: http://developer.echonest.com/api/v4/playlist/static?api_key={shhh.....}&format=json&results=100&artist=Jazz+Gillum&bucket=id%3Aspotify-WW&bucket=tracks
consistently returns back 24 results. There are several more available when searching through Spotify directly -- 80 at least. Is that the expected result?