I don't think you're going to find a filter that would not have clogging problems if there's a lot of silt.

All these filters you'll find for backpacking are designed to address protozoa and bacteria, not silt. Even the ones with pre-filters are going to be falling short with really silty water.
_________________________
"In the beginner's mind there are many possibilities. In the expert's mind there are few." Shunryu Suzuki

http://hikeandbackpack.com