My friend mentioned this just before I published and I think that probably is the fastest largest thing you can get which would in some sense count as one machine. I haven't looked into it, but I wouldn't be surprised if they could get around the trickiest constraint, which is how many hard drives you can plug in to a non-mainframe machine for historical image storage. Definitely more expensive than just networking a few standard machines though.
I also bet that mainframes have software solutions to a lot of the multi-tenancy and fault tolerance challenges with running systems on one machine that I mention.
I also bet that mainframes have software solutions to a lot of the multi-tenancy and fault tolerance challenges with running systems on one machine that I mention.