The standard American football field is 120 yards long and 54 yards wide. What is that in HO(1:87) scale? I'm coming up with 4 feet long, which is crazy and means my math is wrong somewhere.
No, your math is actually quite correct, and you've just done a wonderful job of explaining what's wrong with many model railroads. Most plans try to cram WAY too much stuff in a small space.
My current layout plan is for a 12 x 17 space, but it looks a lot like a typical 4 x 8 layout, basically a big oval.
http://www.modelrailroadphotos.com/photos/showphoto.php?photo=278
Why is that? I realized how much we try to cram into a tiny space. I have a 12 car coal train I like to run. It's a mere shadow of the 100 car coal trains PRR liked to run, but it at least gives a flavor of a long train. 12 cars at roughly 6 inches inches, plus a loco and caboose, and you get a train that's nearly 8 feet long. Suddenly that 11 foot length doesn't seem so big when the coal train is taking up 1/3 of the loop.
Your measurement system is great for picturing this stuff... My layout area is roughly 3 football fields by 4 football fields. Inside that space, I'm trying to put a town, a passenger station, an industry or two, and an enginehouse. NO WONDER IT WON'T ALL FIT!
Unfortunately, many of the layout plans I've seen drawn fall apart when you run a 5 or 6 car train on them, and find out the train fills the entire town area.
If I was working in N scale, I honestly think I'd find an HO scale plan I liked, and build it to the exact same dimensions, only building with N scale track. Think about it, your sidings would be twice as long. Your curves twice as wide radius. The vertical clearances would look much better. It would be sweet.