Originally Posted by prathmann

There's also the Capreo cassette that has a normal range of 9 to 26 teeth. That's not that wide, but the larger cogs on the cassette are interchangeable with those from other Shimano cassettes so one could modify it for a wider range. Here's someone who modified it in the other direction to get a narrower range with closer spacing:
http://rob.ragfield.com/2010/07/capr...ification.html

But taking the larger cogs from the 11-36 MTB cassette and putting them on the Capreo with its smaller cogs would give you a cassette with 9 to 36 or a 400% range.