I put Oxford Custom heated grips on my IS, hooked them up to a Heatroller (stock switch was crap) A Heatroller also works with the Dual-Star types, just hook up Hi and Low to the controller, and get infinitely adjustable heat.
My wife just got a set of Drag Specialties heated grips, they have the switch incorporated in the left grip near the base, very handy. They have them available for 1" bars. The Dual-Star types won't get very hot if used with a grip like the Kury ISO grip, too much air inside the grip. I love my Oxfords- not very pretty, but the heat is excellent.
http://www.denniskirk.com/jsp/product_catalog/Product.jsp?skuId=595763&utm_source=google&utm_medium=csehttp://www.oxprod.com/index.php?pg=3&action=dept&id=137&pid=0&p=I got the "Cruiser" type, chrome ends