I used to work for an FBO and the most common thing that clients wanted was access to the ramp with their vehicles. Not sure if you guys take that for granted in the States but in Australia it can be difficult sometimes.
I also found that most international jets had fuel accounts with Universal or World Fuel Services and that we couldn't compete against them with prices.
My best effort was one night with one other guy. A GIII arrived at 1am. We had the pax clear customs, load 5500 litres of fuel and get fresh catering. They taxiied off the ramp 20 minutes after they landed. I thought that that was pretty fast.