I've got a bunch -
20 or so years ago I bought a full-sized blank firing Uzi at The Sharper Image. The scary part about this is it's to good a replica and could easily accept real parts - or so I've heard. [;)]
I've got an interesting M16A1 - someone made a mold off an original (down to the markings, serial number, etc.). Then during casting they used a real barrel so the handguards and everything back are resin, but the front sight and muzzle are real. Looks really good.
Japanese companies used to import plastic models that were exact replicas - and I mean exact down to the last part and pin. I have a S&W M29 that you can not tell it's a toy unless you actually feel the plastic - it's that good. And the action works just like the real thing. I stuck a set of real S&W Goncalo Alves grips on it, mounted it in a framed glass case, and set six polished .44 Magnum rounds standing up next to it. (Hot glue works great!) Back before the Smoke Free Workplace Act I used to have problems with assholes walking into my workspace while smoking. So I put together this little diarama and stenciled "In Case Of Smoking, Break Glass!" on the front. People thought I was a gun-toting nutcase to begin with, and now I had that whole end of the building to myself. And it was smoke-free. [:D]