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Don't think you are lacking in the lens or camera department. I would just add another sb700 and be done with it.
The SB-700 does not have quite enough power for a wedding. I've been using the SB-900 for the past year and it has never let me down. Put a mini softbox on it or a Gary Fong. Unmodified, the light is very harsh. While most churches don't allow flash during the ceremony, a good flash is still essential. You also need at least three sets of batteries for everything you use that takes batteries. You never know.
Something else I'll mention is that most hobby photographers look at weddings from a gear standpoint. Yes, with the exception of an SB-900, your f2.8 zooms are good enough. However, few hobby shooters are prepared for the volume of shooting and just how fast paced it is. They also don't have an understanding of just how chaotic and high pressured the shooting is. It requires a high degree of organization. Very, very high. I usually crank out about 2,000 shots per wedding, and I'm not a full time pro. They might do twice that. The off camera flash is critical for the formals, but don't kid yourself that just having lights is enough. You also have to know what to do with them for groups large and small. It's difficult working with tired people who are in a hurry to leave, and relatives that might be jumping in and screwing you up. Unlike portraits, you can't go back and reshoot a wedding if you screw it up. There are a hundred ways to screw up and not realize it at the time. Weddings are about 25% gear, 25% skill, and 50% discipline. While all chaos is going on, you must not lose your focus. It's not easy coming up with creative shots under those conditions.
Kent in SD