OneLan seems really good. I saw this one demo'd in some sort of conference once and it would work really well. A bit too pricey, though, I think. Plus I think it comes as an all in one screen and net-top box. What I have here is a few TV screens that were once used for CCTV but I'd like to set them up as signage screens. I've found one called Sedao which might be what I need. It comes with a small box that can be attached to the TV and operated through a web-based client. I'll keep you posted.
Thanks for the suggestions