Robert,
I am completely missing something here. First, I think way too many users blame AC for AC/SQL issues. Most of the offices I have found with issues have well over 15 users and/or computers.
It is hard to say with certainty that it is an interface problem. Amazing Charts support is going to be way behind the curve when it comes to pure SQL Server issues.
I have no idea what you mean when you say that the machine becomes unusable. I also don't know if you refer to reinstalls of AC or of the OS. I have never had to, but if my entire Amazing Charts/SQL Server database became corrupt, I would simply uninstall everything and reinstall SQL. Beyond that I have multiple daily backups.
While VMs are fun to trial different things, and I myself have seven OS on VMWare, running Hyper-V or some very robust VM on a server is helpful for running apps. But to tell the average user on here to NEVER install directly to hardware isn't fair to the average user. The normal user is not going to go out and get Microsoft Virtual PC or VMWare Workstation, purchase a second OS for $150 or more and install to virtual machine.
I don't even think free versions of downloading the two apps one has to install on WIN7 is going to impress too many users. It is simply too complicated.
It takes RAM to run VM especially the ones that don't come with WIN7. If you have 2GB of RAM on a machine, you will likely need to give 1 Gig of that back.
Raja emailed you about help with SQL. At this point, people are going to be on their own on some SQL issues, but with 3500 users, I suspect that most are having no issues at all or Jon's company wouldn't be doing so well. I have run AC on hardware for seven years with not an issue. I am not saying you didn't have one, but I don't see how it happened twice.
I would have to say I agree with Wendell on this one.