I had cruise control kit added as an option to my B3300SU when I bought it. CC kit cost then was $35, dealer installed at no charge as part of the purchase deal.
I'm curious as well, have 8.6 hours on my L3200 & have thought about cruise control a bit already. Not enough to investigate yet, but enough to wonder how much the parts are & if its not to complex of a DIY install... Subscribing.