'speed' => 1000,
'speed' => 2000,
and it will cycle half as fast between slides.
I've dropped it in as an option (e.g.
With the development version installed, you can use change the speed via PHP either via something like:
<?php rotatingtweets_display( array( 'screen_name' => 'your_twitter', 'speed' => '2000')); ?>
<?php echo do_shortcode( "[rotatingtweets screen_name='your_twitter' speed='2000']" ) ?>