I'll say scaled up. After going to that site and seeing their 23% scale version, the launch version must be huge! How is the Spruce Goose flying these days anyway?
The PDF shows the size relative to an alternative lift plane, a modified 747 (with REALLY LONG landing gear). It's not as big as you think, though considerably bigger than SS1.
I wouldn't be a bit surprised to see Rutan/Branson pursue this one themselves, anyway. Who says all of the NASA launches have to be on the NASA built system? If they can demonstrate the capability AND undercut the per launch cost... well, even NASA isn't that dumb... all the time...