Google have written their own UI toolkit for their new mobile OS (not unlike Qtopia). I don't know if that will use X, but anyway that will be seamless to the application developer.

I would guess that it's a question of whether the Perl interpreter can be ported to the new OS, but as you say given that it was ported to Symbian years ago (on devices far less powerful than the ones coming out now) and of course Perl works on Linux, my guess is that it would be possible.

Cheers