Check this Illuminator I've installed recently: Univivi IR Illuminator 6 Leds
It has a very good cover angle, and according to product info on Amazon the size is 4.9 x 4 x 4". I did not measure it before installing it but I think those dimensions are correct.
My old cmvision IR50 (30-45 degree spotlight) recently lost half its LEDs after being installed for 4 years. Just yesterday I replaced it with a Univivi 12 LED model (90 degree flood). It draws about 3-4 times more energy and is quite a lot bigger (certainly larger than 4x4 inches). It provides great wide coverage out to about 40-50 feet on my driveway before it really begins to lose effectiveness. The old illuminator was better beyond that, especially when it was in its prime condition.
Old illuminator, half dead:
This area is also lit by a couple IP cameras' integrated IR, so the difference is not as dramatic as you might expect.