I'm not sure I agree that the niceness of the touch-pad UI depends on the use of Mac OS X. All the other phone manufacturers using the Synaptics touch screen have gone for a Flash-based UI, which I think makes a lot of sense both economically and technically if Flash can hack it, which it probably can. (Remember those good old days when type 1 was the only font format, Display PostScript was all the rage and Adobe wanted to own the UI?) The technology demonstrator certainly included a gestural UI, and could probably have handled two fingers if they had thought it worth while.
The other thing to bear in mind is that, depending on what mood the Feds are in, we might actually be talking about future products over which SJ has had no influence.....
Thoughts on the Next Gen iPod