feijai

See this page for various options. If you went this route, I wouldn't do an 11-34: the jumps are too big, and you probably don't need that low of a gearing, AND I dunno if it'd be wise given the size of the rear wheel. I'd stick with 11-32, which works great and will give you a 31.7 to 92.1. 92.1 is plenty fast for me -- it gets me up to about 20+ MPH, but it's maybe not enough for the more athletic.

You will also need: (1) a new rear derailleur (I got a SRAM X7 Medium-Cage, though probably a Small Cage will work) and (2) a new shifter (I got a SRAM X7 twist shifter, very nice) and (3) a chainring guard or else be prepared for quite a lot of chain drops because a nine-speed chain is thinner and more flexible.

I got a Vuelta 60T from Greenspeed and they're ugly as sin. But work well -- no chain drops. More importantly, when I shifted and the chain vibration hit the guard it made a "bing" sound each time. This I fixed by buying a package of little adhesive vinyl bumper feet and adding them to the guard so that they pressed against the chainring when the two were installed on the bike. Also if you put the chainring on the outside of the crank, the chain is more in-line (reduces drops) and also it's FAR easier to reinstate the chain after a drop. To do this you'll need some spacers and replacement chainring bolts to put the guard further out still, both trivially obtainable at any bike shop.

I am spooked about Capreo: Shimano's not supporting it well and BF has to negotiate with them to even get it. Once you're doing Capreo you're locked into it unless you want to rebuild your wheel again.

The DualDrive is fragile but I like it and think you should consider it.