Onsite digital signage

I have been asked to spec and cost a system to run 10 agenda screens for a conference. Each screen would need to display time sensitive agenda data, session updates and maybe promotional pieces (videos or stills) The content should refresh automatically and would also need to be able to 'push' any updates to the screen if anything changes during the day. Content could be the same on every screen or different depending on location at the venue (and costs) In the past i have used quite an unsophisticated system that ran internet explorer in kiosk (full screen) mode pointing at a live internet URL with a meta refresh of up to 30 seconds that moved to the next page with more content, or even the same page giving me a opportunity to change the content by updating the next page. This was quite time consuming and meant i had to constantly change the content for different times of the day. IE in kiosk mode pointing at a URL (each machine could have a different URL) is quite elegant but it would be good to have some method of making the content display depending on time of the day and also being able to push any updates - maybe using flash Design and layout is important. I would need to be able to change content for 4x3 and 16x9 screens as well as stretch anamorphic content depending on computer output resolution and monitor display