Well, it looks like I will be installing 10.3.5 before the dust settles. Mobilewhack has found out that Mac OS X now supports the HID profile in mobile phones (one of my pet gripes when I was testing the K700i and the S700i), which means I'll never need a presentation controller again - that is, as soon as I get GA firmware on one.
For the non-geek in the audience, this means you can now control your Mac without any sort of third-party software - the phone acts as your mouse and (selected bits of) your keyboard, mapping the phone keyboard to predefined keys according to a HID profile (SonyEricsson bundles three predefined profiles with their new phones - Desktop, Presenter and MediaPlayer, if I recall correctly, all with Windows key bindings).
The übergeek in the audience are free to pore over my notes on HID profiles and try to hack their own - later on, I'll be trying to get the Command keycode straight and creating a SizzlingKeys profile to control iTunes. Watch this space.
Update: the Sailing Clicker guys have released a controller pack called Remote Basics that includes controllers for controllers for iTunes, EyeTV, DVD Player, VLC, PowerPoint, and Keynote, therefore saving me the trouble. So I might end up making controllers for other apps instead.