Looks like the Illusion just includes LED fans (and two extra front fans), as opposed to the non-LED fans in the regular ol' Three Hundred. LED fans will help with the lighting, but the vast majority don't allow control of lighting at all - if the fan's running, the LEDs are on.
So yep it'd be quite easy to replicate the Illusion in red - grab the vanilla Three Hundred, and enough red LED fans to cover your holes (1x 120mm in the rear, 1x 140mm in the top and 2x 120mm in the front), and you've effectively got a red Illusion. That said, the fact that the blue Illusion comes with a full complement of fans for just 15 bucks more isn't bad, at all. They're Antec fans, too - a lot of guys here will tell you that doesn't mean much, but they're certainly not the worst of the bunch. And if they're TriCools (three-speed models with switches), that's even better.
If you want a good, solid light through your side window though, you'll want to supplement with a CCFL or two, or a LED strip or two - as JAE recommended in the post above. For red, LEDs give a far 'bloodier' red than CCFLs do. In a (long-given-away, unfortunately) Lian Li case of mine, I used one of these sleeved LED cables, strung around the inside lip of the case: http://www.pccasegear.com/index.php?mai ... s_id=16004
I Paired it with a couple of mounted red LEDs (like little spotlights) to provide lighting 'deeper' into the case. The LED cable has a switch mounted into a PCI blanking plate so you can control it manually, as did the Spotties. I initially had unlit fans in there, but later swapped in some BitFenix Spectre Pro fans, and a fan controller which allowed me to turn off the fan LEDs:http://www.pccasegear.com/index.php?mai ... s_id=20625
Short of the uber-expensive Corsair Link system, this is about the most elegant fan-LED control system I've run into. The result was a very impressive red, and a lot of money.
The only other case I've seen control fan LEDs was the CM Storm Sniper?, which used big 200mm blowers. I used to be able to push the button on the fan controller and the LEDs would go off - this needed special connectors on the fans, though. By-and-large, fan LEDs are always on.
Just adding a little experience to JAEs good list for you above. Hope it helps mate