hi, i used to carry an arsenal of lenses when i photographed weddings, but with a change in style i found myself sticking to a single zoom lens. And even then most of the good photos were at the wide end (17mm - 19mm). You can see examples of my shots at http://photo.hurricadia.com
So i think it's really down to style. If you do tend to shoot lots of closeups at weddings you;ll need some quick flexibility as people are always asking for group shots or something that needs a wide angle.
In a wedding, there will be lots of people. Not all the time, you are able to move far or near enough for that perfect frame. Most of the time, its fast paced. No time to fumble with changing lenses. Planning is key. By looking at the schedule and location, you know you can afford to use your prime lens.
If you must, carry 2 cam bodies and favorably studio lights unless you have your flash attached at all times, even outdoors (just in case).
Wedding pictures means a lot to the client. For most people its once in a lifetime so we cannot afford to miss any shot.
If it is film, I done that many years ago, at that time the Zoom lens was horrible, also cant afford the 35-70 2.8 during than.
When I switch to AF camera, using 24-85 all the way, with some fisheye lens shots.
My friend shooting wedding with prime lens only, 20mm, 24mm, 35mm, 90mm, 135mm with two F80, but according to him, 24mm used on the most of the shoots, and he switch to digital this year, mixing zoom with prime.
IMHO, for digital, is not advisable to change lens to often, unless you dont have a dust problem.
Im talking about only one and pro photographer for wedding, so the setup must be practical and efficient, so using prime only doesnt imply not workable, it also very much depend on you style.