Been debating on whether or not to post this as I don't know if these grips are available anymore but I thought I might as well in case someone is interested. I've always run heated grips on my bikes. The ones I found that worked best were sold by Show Chrome as grips for 1" handlebars. I've used at least four sets of them so far and never had a problem once. The thing I like about them is they have a continuously variable control so you can set the heat to whatever you like.
I had a set that I bought as a spare a number of years ago and finally decided to put them on my CB1100. What I did to make them fit was to cut off the ends with a hacksaw to clear the end weights and to shim up the bars using wraps of nylon non-adhesive self sticking tape. The old grips I removed by cutting them off with a box cutter so as not to damage the throttle sleeve. I then wrapped the nylon tape until I had a snug fit and then glued them on with grip cement. I did the same thing on my Yamaha Maxim and they have held up quite well for over 7 years. The nylon tape has the added advantage of insulating the grips from the bars so you get even more heat.
I paid about $50 for the grips about 5 years ago so if you can find a pair, they shouldn't be too expensive. Far better than what Honda charges for theirs.
Here's a picture: