A bluetooth keyboard or mouse should work with iOS 5, though I haven't tested this myself.

The best solution for a corporate presentation however, assuming the facility can accommodate an HDMI connection, would be to pick up an AppleTV and then use video mirroring or whatever other airplay feature is supported in iWork apps. This way the iPad is the remote.

The person giving the presentation, holding the iPad, will even be able to read all their notes and other presenter information that shouldn't/won't be displayed as part of the presentation through the AppleTV (and projector).

No wires connected to the iPad. AppleTV with a single power cable and HDMI cable.

I'm doing a bit of consulting for a friend who's currently part of a task force at his fortune-100 workplace to determine how they can better use technology in the workplace. He's already intended to look at the iPad and this was one of my suggestions to him.