One of the things I've been considering with Emprise!™ is doing things in real units of time. That is, rather than segments, rounds, and turns, things would actually be listed in seconds, minutes, and hours.
With spell-casting, this presents little problem. It's simplicity itself to say that a spell takes 36 seconds to cast, rather than 6 segments.
In combat, on the other hand, things get a little dicey (heh... no pun intended). Initiative is a pain in the butt enough already without having to time things down to the second, which I'm afraid this conversion might lead to.
One solution might just be to round everything to 10-second increments, so that there are 6 possible points of action within any given minute. But that has me wondering if it's all that different from the current AD&D system of 6-second segments, 1-minute rounds, and 10-minute turns. I don't want to change things just for the sake of changing them; any changes I make are going to be done with the intention of making things either easier or more fun.