From version 8.5.0 of the Nuevo plugin it is possible to define a completely custom set of speed rates. The plugin simply accepts video.js playbackRates option, which is an array of custom speed rates. In the video example above custom speed rates are: 0.5, 1, 1.5, 2, 3 and 4. And video.js setup is as follows:
var player = videojs ("my_player_id", { playbackRates: [0.5,1,1.5,2,3,4] });