Only just took possession of my Focus on Saturday, however I did do some testing.
Took a trip that was about 100km each way (62miles). On the way back, I reset everything with trip 2, then kept the speed around the speed limit of 100kmh (62mph). At first, the Fuel indicator came up at 8.5litres/100km, or about 27.5 US MPG. However every 3 seconds, it would drop by .1. So 8.4, then 8.3 etc.. It did this until it went down to 4.9, or about 47 US MPG. I was able to hold it there for about 5 minutes, but then after some large hills, it went up to 5.1, or about 46mpg.
I could not calculate by hand (still on the first tank), and the computer is probably a little optimistic, but considering the engine is very far from being broken in (only 300km on it right now), that is still not half bad.
Just for reference, Titanium Hatch w/ 18' summer tires and sport handling, regular 87 octane gas.
Have a long trip coming up which is about 550km each way. So will see what I can get.