I have Ergon GP3's from here on my Dahon Mariner:
Amazon.com: Ergon GP3 Bicycle Handlebar Grip, Large: Sports & Outdoors
I used a knife to cut the right side grip and make it shorter for the twist-shifter. It uses an Allen Bolt to tighten, but it works well. Make sure to use a rubber mallet to bang the grip completely on the handlebar, to ensure the allen bolt-driven clamp is truly clamped on the bar completely.
-Warr