I hate to say it, but if you found a vendor that 'guaranteed' virus free plants, you would probably not be able to afford to purchase them - such a guarantee would be next to impossible to keep and I would think it would open them up to lawsuits if they sold even one that was virused. Virus should not be treated lightly in my book, but as you say, many don't really seem that concerned about it.
The best you can do is deal with a reputable dealer that has been in business a while who is concerned about pleasing the customer base; such a dealer would be glad to replace a sick plant or refund your money, or they lose their reputation.
I don't know about Hausermann's in Chicago's virus policy because I have never bought an inferior / diseased plant from them, but they go the distance to make customers happy and I can't imagine that they would not be glad to replace a plant. This would only cost them a matter of small change - testing each plant or making such a guarantee would cost them much, much more.
Again, deal with reputable suppliers, test your own if you suspect disease, and ask ahead of time about replace/refund policies. That's about the best you can do.
Sorry, but that is all I think you can expect.
Steve