We are using RDC as well on SBS 2008 R2. I would submit that if you haven't already, take a look at the remote app features built in to your session host configuration. It allows me to host AC, and effectively "push" it to clients through a web portal. To the user, it looks like it's running locally, and allows me to install updates to AC on 1 machine (our server) as opposed to installing locally on every box we have. I think 2x has a similar alternative, but I haven't really seen it in action - (though our billing software is based on 2x, and it seems like pretty decent software).
