I just bumped into this
http://store.pixelfilmstudios.com/plugin/plugin-prowall
I want to use video walls in my editing, and just want to know the easiest way to do it
MacBook Pro with Retina display, OS X Mavericks (10.9.1)
The easiest is probably just to use a plugin such as the one you linked to.
If you don't require a "professional look", and only need a small number of clips in your video wall (such as 4), you can easily do it "by hand" in FCP X: just stack four clips (i.e.three connected clips to one clip in the primary storyline) and use the transform tool to resize and position them as you want. This becomes a lot of work for more clips (like 12 or 16), not to mention that your timeline will look a bit weird.
Another relatively simple solution is to create the video wall using Motion. A very nice solution using a Replicator is described here in under 5 minutes by the great Mark Spencer:
Making a video wall in FCPX
