After watching 'A plane is born' and 'a chopper is born' on Discovery Wings, I can't imagine building something like White Knight. Would take 15 years on your own. I suppose it would be possible with a team of 5-10 people over awhile though.
Maybe they'd have local clubs that could build one?
White Knight and Stretched White Knight would be a problem for amateurs, but SS1 would be a task worthy of the effort. You should be able to build an EZ-SS1, and transport it to the Mojave Spaceport where the White Knight could be hired by the launch. Not cheap, but what use is all your money you've been squirreling away for a 4X4 you won't be able to get gas for anyway?