If driving has taught us anything - it's that requiring everyone to do anything is futile. Even bad drivers can pass a driving test. Then again, as George Carlin said, "Everyone in front of me is an idiot, and everyone behind me is a maniac". Can you tell i've given up? sigh.
I noticed that you didn't mention Mosso, one of the first large scale cloud providers that has been doing this for years. They are a division of Rackspace as well.
As far as robustness is concerned, there was a great write-up of the Mosso platform last week on this blog:
http://matthewsacks.com/techblog/2008/09/23/rackspaces-mosso-hosting-cloud-review/
It's not just a regular keyboard. It includes weighted keys also. I bought one off of thinkgeek about 2 weeks ago and couldn't be happier with it. I am very impressed.