I don't know there is any reson that you couldn't have a Smartphone version of Pocket Streets. Based on the layout of the devices the touch screen only has a few advantages.
Zoom in and out can easily be controlled by various buttons.
The zoom over an area feature could easily be duplicated by using a specific feature to place a cursor on the screen use the D-pad to place it at the starting point, press the action button, move the d-pad to the end position press action again and zoom in on the area. Maybe provide a way to scroll through the locations in the viewable area. definitely not as fast as a stylus, but still fully do-able.
8O I didn't even know DTMF was legal. I thought after the Cap'n Crunch
(is that the right guy?) escapade that it was frowned upon by the phone companies and the feds.