Here are some logo's that I put together in Photoshop a while ago, the top one is based on Silent Running
This one is from the film Saturn 3 with Kirk Douglas and Farrah Fawcett-Majors.
This is from The IT Crowd, the Channel 4 comedy series with Richard Ayoade, Chris O'Dowd and Katherine Parkinson.
And the last one is from Aliens, the logo on the Power Loader's leg.
I've did these as large size PSD's for putting onto T-Shirt's, the only one I've done so far is the Saturn 3 one, and that's looking a bit faded now as it's a few years old.