Well not really. 
United Launch Alliance is now offering a “build your own launch vehicle” pricing page
It’s kind of neat - I went and tried to build a SpaceX Falcon 9 5.5mT GTO vehicle and it came out to $70M.
It’s not KSP unless you can strand a Kerbal on the moon. By accident. Or on purpose.
True - really want it to let you hit the spacebar and have all the boosters fly off while the main stage sits stock still.