I was browsing around on Gun Broker, and a "Demilled Gas Operated Marlin 336 30-30" showed up. I thought I have about seen it all, but this baby takes the cake. If someone can post a picture of this abomination, I'm sure everyone will find it interesting.
It is kind of a hybrid of John Browning's gas operated '73 Winchester and a gas trap M-1, but made by a 15 year old in the farm's blacksmith shop!