Other Sphere computers exist although they are rare. This particular Sphere computer is one of a kind because it is the one that belonged to the founder of Sphere Corporation, Mike Wise.
David Larsen has a great collection in Virginia. He has managed to save two Sphere computers.
Scott Adams tells how he sold the Sphere he bought years ago to a collector in Florida.
The Computer History Museum has two Spheres...a System 320 and a System 330. Both look to be kits or, perhaps, have undergone some "modifications".
For more information, click on the link(s) below. David Larsen's Sphere computers