I would think a straight tube would work as long as it catches the dirt - that's the purpose of the oil-bath canister. Basic principle - gotta give it air and make sure it's as clean as possible.
I probably won't do any of the stuff to the jeep that i was talking about on the other thread but i'll put on a regular intake because the canister one is broken/rusted.(good run on sentence!)
I'm going to put on the most free flowing intake I can find but still have maximum dirt/dust catching. plus I 'll probably make it into a snorkel type thinga majig so it doesn't clog with dirt or injest any water.