There is now a (mostly only Japanese language) on-line tool to enable anyone to produce simple Miku animations. It comes with a selection of Miku phonemes in different 'tones' I suppose one could call them, each with a note-length animation. There is a rhythm track, and a selection of five bass lines (or none, if preferred). There is also a simple guide to how it all works – again, in Japanese.
As far as I can work out, the 'building blocks' have been provided by Daniwell – which could certainly explain the couple of cat-like sounds within the sounds selection, of which there are nineteen in total, plus a twentieth 'blank' button to remove a sound from any of the boxes in the composition area. Nyah-nyah!
I've had a quick go, and here is my little of nothing, really – but it was fun to give it a shot. Click the Play button (right-facing arrow) to play the auto-repeating short phrase I have assembled.
I shall probably practise playing with this during the days and weeks to come, and perhaps one day will actually be able to produce something worthwhile. Who knows? I shan't know until I try...