My boss put a set of 20's on his F150 and I gave him a lot of crap about it until he actually got them mounted up. Surprisingly they don't look like big ole dubs, they actually fit the truck pretty well. If you're not rock crawling then you don't need all of that sidewall for flex and grip, just a bit of a taller sidewall to fill the wheel gap once you put the levelling kit on.
Rick