Whats wrong with a throttle lock? A non mechanical (in the sense where it doesn't physically lock your throttle) still needs be activated either way. but if you are looking for a real real CC
http://www.webbikeworld.com/t2/motorcycle-cruise-control/Thats the only thing ive ever seen. (they have a bunch of stuff on that site, so snoop around for the a throttle lock) I have the palm thingys and i prefer that since i don't trust a cruise control device that holds my throttle in place.
Also check out this thing.
http://www.brakeawayproducts.com/productinfo.htmlI do long commutes on freeways. I wanted something that would modulate speed as well.
I was considering the Brakeaway Product. I e-mailed them for availability