Ah, yes. Being slightly more annoyed at my upcoming trip, I decided to take another look at multi-platform screen-sharing, and after looking at ways to optimize network traffic I eventually decided to search for multicast solutions.
Multicast happens to be the first topic of the latest Cringely rant - a piece that I believe to be particularly misguided, although he does raise a few interesting points regarding Precept's IPTV solution and its acquisition by Cisco.
As usual, however, he throws in just enough fact to make the rest of the article palatable, and focuses on spinning the issues so far out that people in the know, well... cringe at his cluelessness (pun intended).
Multicast works, and the reason it doesn't work as it should on the open Internet is that 99.9% of network engineers and home router manufacturers just don't want the hassle of implementing and troubleshooting it.
But even if it's not widely used, it makes perfect sense to use for LAN presentations, so I eventually came across the MulticastVNC page, which in turn led me to the TeleTeaching Tool Download Page, wherein I found the name of none other than my fellow planeteer, Dominik Wagner (he of Coding Monkeys fame), who packaged it for the Mac.
At first sight it does pretty much all you'd need as a basic presentation tool (and then some), plus a few other things you wouldn't expect from a Java-based application.
Now all we need is a Cocoa application like these - one able to broadcast the contents of a PDF or Quicktime movie, possibly exported from a PowerPoint or Keynote presentation. It doesn't even need to do video.
And let's be honest, there's not much need for application sharing. Annotations, sure, but there is no point in, say, extending Keynote to do all of this (and it would be nice to be able to watch using a simple VNC viewer).
Now, paging through a landscape PDF is supposed to be something you can do with moderate ease via Cocoa, and there are umpteen ways to grab the image and send it off (i.e., plenty of VNC code out there), so something similar to Windows Collaboration that lets people find and join presentations should be more than enough.
Obviously, allowing viewers to download the presentation and auxiliary files set on a "shelf" viewable by both presenter and viewers also makes sense... Who's up for it, then?