I did this as a mod to my GTR1400 about 4 to 5 years back.
Was looking for a throttle lock and was shocked at the price of them especially the bar end type, then I found this on the web - http://www.murphskits.com/catalog/docs/Rostra%20install.htm
I decided to go with fitting the Rostra cruise control and have been more than chuffed to bits with the results, I can engage the cruise from around 35 mph upward and holds the set speed very accurately with no hunting, it cost me around £150 at the time so would think will be a shade dearer now but was worth every penny.
Oh yes if anyone has doubts about safety it is disengaged by using either brake or pulling in clutch lever and of course by cancel button.
The instructions are very good and all the parts are available on the web.
I did a minor alteration to the bracket fitted to the throttle stop on the carb but otherwise all same.
If anyone wants any more info I am only too glad to help.