I would recommend DMR V8s. I've used them on my mountain bike for years. They take a lot of abuse and in my experience offer more grip than cages. You still get shin digs, but they tend to focus all the force into a smaller area, so you end up with lots of small holes in your shins rather than scrapes. I have a pair of the Wellgo copies on my trials bike at the moment and the pins are standing up well to getting scraped across walls, though as someone said earlier it's probably wise to loctite the pins in. http://www.chainreactioncycles.com/Models.aspx?ModelID=563