Welcome to our lair! I'm sure we'll all do our best to help out as much as possible. Could you be a little more specific about what it is you're hoping to do with this project? THe impression I recieved is that you're thinking about building 5 speaker cabinets with 4 drivers in each? Or am I off the mark here? (I'm not feeling at my sharpest tonight, so the fault is probably mine)
Assuming for a minute that my guess is correct, you'll need to remember that 4 drive units per box does not a line array make. This is not knit-picking over the name however; it's something you'd need to seriously bare in mind, because of the dispersion of sound, or lack thereof that you'd get with such a short line. The advantage of a line array lies primarily in that they effectively always place the listener in the nearfield, negating to a major extent reflected sound from the room. With a short line, this isn't going to happen, and you're going to run into all sorts of problems regarding image placement for example. In very basic terms, the image is being stretched just enough to get all the drawbacks, but not anything like enough to recieve any of the real benefits of an array.
A properly set up line array is great, but they're tricky to get right. Arrays using full-range units (which I suppose these can be just about classified as -look like nice little drivers by the way) are also often less sucessful than 2-way types using mid/bass drivers and tweeters. With some hefty power-tapering though, they can work well.
Best
Scott