If you are really looking for a tilt/shift lens for wedding photography, you should probably at least look at the TS-E 24mm f/3.5 L, in addition to the TS-E 45mm. I've seen a number of photographs from very good wedding photographers, and the majority seem to use the 24mm if they do creative focus. That said, the TS-E 45mm is the second most used lens for wedding photography that I know of. One of my favorite wedding photographers who uses T/S is Sean Flanigan, a wedding photog in Seattle, WA. His work is quite amazing (although for more than just using T/S, and is a great example of how to apply creative focus (most of which I believe is done with the 24mm given the wider field of view, although the 45mm may be in the mix at times as well):http://seanflanigan.net/blog/page/6/
Another great T/S wedding photographer is Bobby Earle. He is quite skilled, and uses both the TS-E 24mm and TS-E 45mm lenses. I will point out that there are quite a number of similarities between Earle's and Flanigan's work...tilted, desaturated, grainy, often black and white with high contrast. Not sure if that is simply a strange coincidence, or if it is the consequence of using creative focus...maybe it has a concurrent narrowing of style while at the same time offering greater freedom. Anyway, these two photographers should be more than enough inspiration, regardless of whether you pick up the 24mm or 45mm. And, according to Earl, he really loves the 45mm for vertical wedding portraiture.http://bobbyearle.com/blog/tilt-shift-lens-use-in-weddings/http://bobbyearle.com/blog/tilt-shift-lens-tips-for-wedding-photography-part-2/
The real edge the 24mm has over the 45mm is a far newer optical design, and sharper optics than the much-vaunted EF 24mm prime. The 45mm is an older design, and still has some flaws. I can't say I've ever noticed that actually mean anything in the creative focus wedding photography I've seen (although again most seems to be with the 24mm), but it might be something to think about.