Can you please recommend affordable real time chroma keying hardware? I need to pull real time blue screen for the news and weather forecast backdrops. Right now I need SD keying but real soon I will also need HD. I was looking into Ultimatte products but they seem a little pricey. Thanks.

Not sure what equipment you have already or what your full budget is, but Conduit Live for the Mac can provide a real-time keying option at a relatively low cost:
http://www.lacquer.fi/conduit/live.php

It's available as part of the Coduit suite from dvGarage as a $199 software solution: http://www.dvgarage.com/prod/prod.php?prod=conduit2

If you don't have the hardware to run it, then obviously that would have to factor into your "system cost", but it might be worth a look.

As a disclaimer .. I realize that my last two posts have directed people to this software, but it's only because I've seen and used this software and do believe that it is a useful option to look into. I'm not employed by dvGarage or Lacquer and receive no form of "kick back" for posting. I'm just one dvInfo member trying to help others. :)

Have fun.

if you can find for cheap a VIDEONICS MX-1 video mixer, there is a nice chroma key feature.