Non-time bound charts

[ketels]

Would it be possible to support a graph that renders the given data (eg via data_generator) without being bound to having the graph_span?
In my case I'd like to gave an electricity price graph. And since the prices for tomorrow are released at 13:00 I can't set the graph_span, since it's sometimes 1d and sometimes 2d. Therefore I'd like to provide the data I have and have the graph simply start at the first timestamp given.
That would also make it quite easy to have a span between now-2 hours and "end of the array" rendered.