Answer to your question on the 747
 

US Air Carriers that fly 747s:

Atlas Air (Classic and 400, North American launch customer for -8)
Polar Air Cargo
UPS
Kalitta
Evergreen
Southern Air
United
Northwest
Cargo 360
Focus Air

... that's all I can think of at the moment.

Carriers outside of the US - many.

Just to keep the aspiration level reasonable the following alternative list is for those who can't get on flying with US part 121 747. NASA has at least 1 747-100 (I think two) to reposition the Shuttle and a single 747SP for infra-red astronomy. The SP was to be contract flown by first by United pilots, then Evergreen pilots, but I'm no longer sure who's going to do that - the program is only about 6-7 years behind schedule. Then there's the 747-200's in the Air Force inventory for the presidential flights. There's also a semi-experimental 74 the AF uses for quasi-star wars stuff. I'm surprised there isn't a US based billionaire with their own private 747.