A lot of Tablet PCs now have dual digitizers, some of which work just as you state with a button toggle between them, others that are in touch mode all the time until the pen nears the screen at which time the active digitizer is switched on.

The answer to this problem seems so easy that there must be something to this that I am not aware of here.
Why don’t they just add an on-screen button that will let you switch between Active or Passive as the need arises? Then you get the best of both worlds.
This could perhaps just be a firmware upgrade or software patch so you could go back and fix all the one already sold.
How about a patch and a new screen pen combo?
The pen could have a clicker on the top (like a reqular ball point) that quickly switches between Active or Passive.
I almost feel silly posting this note.
This seems so obvious.
Later!
The Web Hunter

He missed one important difference between the two technologies… If you lose or break your pen on the active screen, your pretty much stuck until you get a new one. The workaround for resistive is pretty obvious.

-SK