I primarily use volume charts with a minute chart just to keep an eye on volume. I am looking for a simple indicator that will plot as a bar the time it takes for a volume bar to complete to function as a volume proxy. So it would look like a minute chart with volume bars, but be instead a volume chart with time bars. A short time bar would equate to a high volume for that volume bar. If it too a long time to complete the volume bar, the time bar would be higher. Simple. I'm not much of a programmer, so looking for what may already be out there.
I'm not much of a programmer either so I can't help with that, but I understand what you're getting at. Have you ever looked into delta-volume bars? There are a couple of threads on TL about it. There is also a "bid/ask volume difference bars" indicator on Sierra that I just started looking at today. I don't know exactly what Ninja has but I'm sure that they have something similar. It's not exactly what you were asking about, but I think the basic concept is the same.
I stand corrected - on Sierra there is a "bar time duration" indicator. I bet Ninja has something similar.