You can try Airsoft Extreme, I bought a metal Glock 18c from them, but that was over 4 years ago so I'm not sure if they still carry them. You will probably have to contact them direct about this though. I'm nto sure if their current metal slide glocks have trademarks anymore.
Another place is here. Down side is this airsoft shop is in Hong Kong. Upside si they're a reputable shop