Black Hat or Not? Linking technique using PHP

[HitsChatter]

I had an idea that I wanted to see what people think of it. I'm optimizing a site that is already built w/ very generic file naming and directory structure. In other words, I don't have directories or file names that intentionally have keywords in them. For the most part, its just a lot of index.php and one-word names.

So now I'm trying to figure out a way to get some keyword URL's in there w/o trashing my directory structure.

Here's what I'm thinking:

Let's say I have a link already in the page that goes to index.php. What if I changed the link to keyword_term.php, then I put the following code in keyword_term.php:

<?php
$no_spider = "TRUE";
include "index.php";
?>

index.php would then have this in the header:

<?php
if ($no_spider = "TRUE") {
echo "<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">";
}
?>

I know it seems like more work than its worth, but the idea is that in the long run, I can optimize multiple pages for different keywords, while requiring little maintanence if I decide to edit the original index.php. I'm also using the $no_spider variable to aviod being penalized for duplicate content. My intention is not to get index.php indexed multiple times, just to allow other pages to link to it using different file names.