make you're own GridAxisDraw child class with own grid style drawing (or maybe I could push further into Chameleon capacities)
Add time custom display format method (The exact same format is not available out of the box)

For all the zoom/scroll, verything you need is available.
There is also a Linking feature that allows to sync axis between graphs (when one zooms or scrolls, the other ones follow) : maybe you could use this to link to you're grid to the graph Y axis