Digital Signage Mac OS X, Xserve package, Digital Hub

this is probably better left to a third like all the other links you posted. if you really want it on an apple ask one of them to develope it on a mac.

 

Apple has a root certificate authority. It supports numerous others. What do you want from the company that you can't get now?

 

Digital Signage Application for Mac OS X

There is a new Digital Signage Application for Mac OS X: ~sedna presenter. It allows users to manage, schedule and deliver digital content to any display, from single-screen delivery to perfectly synchronized multichannel, multi-display video walls.

Here's their web site:
http://www.sedna-presenter.com/

 

Since you guys posted this, ~sedna have not only released Version 2.0 of the Presenter family, but they've also released Presenter Control Light which allows the playlists to be invoked from an iPhone/iPod touch as well as Mac.

There's also an entry-level product (Presenter Player Light).

There are many distribution partners around the world now: refer to ~sedna's for more details.