I have. Most observatories have the equipment.
Why is it that re-building the Saturn-5 is impossible today?
Money.
Or, to be more precise, it's not impossible, just pointless.
Technology as advanced considerably since the 1960's. NASA has become a political tool instead of a military organization and is thrashing about for a mission, and bleeding funds while doing it.
If we had sufficient reason to need a booster with the capability of the Saturn V, Northrop/Grumman or Boeing would have no trouble building one once properly funded to do so.
Check again, supposedly the plans have been lost??? The single greatest accomplishment of man off earth and the plans are lost??
We better get a new crew in at the National Archives.
They also lost Kennedy's brain.