Disclosure: I don't do wedding videography. But I'm dubious about the value of most of the workshops I see. If you want to get into higher-end weddings, here are three key elements:
1) Work the wedding planners
2) Work the wedding planners
3) Work the wedding planners
If you are looking for an angle to sell, try something like this: "Your brother-in-law can shoot a wedding video. I'm going to provide a Hollywood production, with the bride as the star. Not only will the movie be memorable, but the process of making it, with your daughter as the star, will be the most memorable event of her life. She will never forget it, and she will love you for it as long as you live!"
That sort of pitch, combined with the appropriate entourage for the shoot (makeup, lighting, audio, and so on), a bit of champagne, and a couple of jib shots, should get you where you want to go.
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