Minutes don't appear as an option, at least for Vegas 13. I can't imagine a groundswell of demand for new time code formats. Personally, I'd like to get rid of some formats that exist already. If you want a counter that increments without the distraction of minutes:seconds, you could use seconds or absolute frames. Neither, are what you really want. 

Some scriptor could probably take the seconds counter and do a seconds/60 conversion to display minutes.