If you're actually looking to do something like this well, either go with Citrix or Windows Server 2008 Terminal Services.
http://download.microsoft.com/downlo...n2008TSTWP.doc
I personally like Windows Server 2008 Terminal Services, and I think it has a lot of flexibility in this regard, but it definitely must run on dedicated servers. However, it may be cheaper than Citrix, in that you need Windows Server anyway to run a Presentation Server solution. TS also integrated into Windows nicer, IMHO. I think the TSRemoteApp idea is really, really cool. I wrote a
blog post about this, but my I'm working on my server, so that's may or may not be available (here's the google cache of it:
http://74.125.77.132/search?q=cache:...ient=firefox-a)
If this is something you'd like to play with, PM me, and I can give you an account on my test TS system.