[jdh]

For what it's worth, I'd be satisfied just with having "Focus" in the iPhone version for now, if perspectives is too unwieldy to try and code.

At least "Focus" would get many of us part-way there, and would likely solve the OP's problem. I also suspect it would be easier to implement from a design point of view then trying to get into perspectives, which might not even translate properly from the desktop to the iPhone.