I share your appeal for such complication. Patek masters it very well considering the traditional legacy of such a brand and the way they master the volumes of the watches they offered (which is a complication on its own versus making big sized watches). It is always possible to add details but at the high cost of volume. A matter of choice from the brands. Patek I think makes the most refined and elegant of them.
Your suggestion is very interesting. Each time the 30-minutes makes a turn, it pushes a counter (wheels+disk). Then the reset function is coupled to both displays.
The thing is that, when I see the dial serving as a briudge, it would really need to be simple:

I'm not a watchmaker but it sounds as a very nice alternative even if I don't know if it would be simpler and less complicated. But certainly something to propose to the brand! Register the patent!
Thanks Anthony 
Cheers, Mark