I wanted to use a realistic spacecraft, so I decided to go with the Dragon. It really ate into my fuel, I only had 29.18% of my fuel left by the time I reached the ISS -- but it took me 2 hours and 29 minutes to reach the 400m point to the ISS. That's not my shortest time for a "realistic" rendezvous, but it is the shortest time it's taken me to use a currently existing spacecraft to the ISS. My shortest ever rendezvous was around 28 minutes using the DeltaGlider, launched one then launched another one to chase up with it, both from KSC.