I also have wrist issues and would really like "real cruise control" but the cost of $800 and the amount of work is not worth it to me.
I have a "Go Cruise" throttle lock. Although a big help it, as most throttle locks, only lock the throttle at one speed which works well for me to get some relief unless I am on winding back roads that require constant throttle changes.
For about $30 it is a great addition.
http://www.2wheelride.com/GoCruise_t...0control2.html