hmm after a little sleep, it seems i managed to come up with a working one, no idea if its the most economical or not.

Code:
/use [modifier:shift] vengeance of the illidari
/cast [modifier:shift] elemental mastery
/cast [modifier:shift] nature's swiftness
/cast [modifier:shift, target=focustarget] chain lightning
/cast [target=focustarget] chain lightning
anyone verify this is ok, it works well ingame, but there might be an easier way.