I think you will not find a suitable calendar application replacement for the BlackBerry. And since there is probably little demand for one, I think you're probably going to have to get used to the options the native app provides, or find another phone.
The "Weekly view" doesn't give you the multi-day bars you want, but it does shade those days and present a caption at the bottom. Perhaps you could get used to that?
I've grown accustomed to switching between daily view, agenda view, weekly view and monthly view, according to what I'm trying to get done with the calendar. Good luck!