I like entry 26 but fear it will be difficult to fit into our website comp given how tall it is. I'd also need to see it reversed in order to know if it would look good on a dark background. Entry 21 has promise if you incorporated some of the elements of entry 26.
#45 can be used in your layout putting "half of the square " on Dark Blue background and half on "white background........This will make logo pop out of the flat layout.....giving a little shadow below the square it will do the magic and gives it a depth .........The logo can be used as a "Sticker" and media / Background independent