It looks like the folks over at Intelligent Assistance have figured out a way to translate FCP X projects into FCP 7 timelines. Project X?7 is a $50 XML translator that takes your FCP X XML file and translates it into something that FCP 7 can understand. Once in FCP 7, you can then take your project to a number of different applications, including Premiere Pro, which is the gateway to Dynamic Link with After Effects and other Adobe apps.
Project X?7 looks like a pretty solid plugin that appears to do what is asked of it. Check out the screenshots below for a comparison of FCP X to FCP 7 projects.

FCP X Sequence (before)

FCP 7 Sequence (after)
From the “Help” documentation:
The translation from Final Cut Pro X project to Final Cut Pro 7 sequence isn’t perfect. Here’s a list of what gets “lost in translation.”
• Compound clips
• Multiple speed changes in a clip and keyframed speed changes
• Effects
• For titles, font, size and color information does not transfer*. Some titles with complex builds may have the text out of order in Final Cut Pro 7.
• Transition settings* • Color, Transform, Crop and Distort adjustments* • Audio levels and audio enhancements* • 4K media files (Final Cut Pro 7 supports formats up to 4000 pixels wide)
* we expect to support these features with a future version of Final Cut Pro X
If you’re wondering why the app doesn’t go the other way, here’s what Intelligent Assistance has to say on the Project X?7 product page:
Before you start sending emails asking why we didn’t do the opposite, since that’s what everyone really wants, let me explain. Back in my initial briefing for Final Cut Pro X, I asked about the transfer and got the distinct impression that someone was already working on it (perhaps even Apple, it was vague). We’re a small software developer and can’t run the risk of spending considerable development effort to discover that a better funded competitor will come out with a similar product and kill our sales. (emphasis mine)
I just paid for the download what the ??? where is my serial number?