Any luck with this? I wanted to ask about it and what you're asking I'm also looking for the same exact thing. Found this online and can't find any reviews besides a couple about this guy on the vendor forum here. The package is quite expensive and I literally just want this.

ZoneTraderPro Cumulative Delta Indicator

I'm currently working on it, but it's more complicated than it seems on the surface (I think). I wrote an indicator (still tweaking it) that I can set in low, medium and large block sizes taken from time and sales, but it doesn't give a complete picture as nearly all orders on T&S will be less than 4 contracts. The ZoneTrader uses T&S plus monitors the order book for large limit orders and then monitors them to see if they eventually get executed or cancelled. By comparing the two data products (order book and T&S) you can build a more complete picture. I may attempt to add that feature, but I haven't played with the order book enough yet to know what data is available and how fast it's delivered. The algorithm to monitor the book is a bit more complex than your plain indicators and I'm not sure how much it will slow your computer system down when running.

Theoretically, the investment in the ZTP could pay for itself in short order.