Right all, sorry a little time away.
I have put in pattern looping, and everything works pretty nicely.
It needs global load and save - I may get round to these if any demand.
Also I had to resort to using a plugin in the end, in order to get values from js back into construct 2 without really bad hacking.
I want to follow other directions on related audio projects at the moment so I have opened it all up by putting the whole source on the lovely github.
If anyone would like to do some better graphics I would be much obliged - there only needs to be a knob, piano button, tab, etc - about 6 assets total.
I dont think there is more that can be done with TML5 audio than this until the WebAudio stuff by google really kicks off properly on all browsers.
So, https://github.com/mrchay/c2synth for the whole project (put the plugin into your plugins directory as you will be accustomed, i have modified it a little I think to give more robustness, nothing major)
The working latest is at http://bassmoi.com/c2synthbeta for now