You have a 50MM throttle body now, on the 3.0l Vulcan engine
The Ford Escape 3.0l Duratec engine has a 60MM Throttle body, and will bolt on but does require modification, there are "How-Tos" for this
Morana Racing offers bolt on intake/throttle body parts: Tom Morana Racing Engines
No on the 4.0l/5.0l throttle body
Yes, unless you are changing the engine parameters, so it needs more air, putting a larger throttle body on doesn't really do much.
Like putting on a larger air filter doesn't do a whole lot for performance
Automakers don't tend to want less performance from an engine, so usually don't restrict intake or exhaust flow, for that reason.
But cost is also a factor, a fan clutch is less expensive than an electric radiator fan, so you have a fan clutch.
If you want a little better performance and better MPG then changing to an electric fan will for sure do both, not much but not 0 either