Incentive leads are huge thing in mainstream and are allowed on certain campaigns. We have many merchants which do allow them (see the list I posted), and provide sub-ID tracking for you to handle the incentive part to your surfer/member.
Long term, lifetime commission programs do exist, but are somewhat rare. Webhosting merchants come to mind. They all deal outside of the networks, so I can’t comment on them much.
Thanks
JP Sauve
http://www.maxbounty.com