I think leasing can work for a domainer if he/she owns a really high quality domain.
How do you know if you have a high quality domain someone would lease?: IMO, one indicator would be if people have already contacted you (unsolicited) to sell the domain.
For example... the same guy calls me about once a year and asks me to sell one of my domains... next time he calls, I might suggest he lease it.
Here's an interview with the owner of LeaseThis.com, click the audio player...
dnjournal.com domain leasing article...
http://dnjournal.com/articles/companies/leasethis-january2007.htm
IMO, domain name leasing could be alot like the commerical real estate business...
IE: a major investor owns a shopping mall... small business lease space inside the mall to get the foot traffic they need to make his/her business successful... as with commercial real estate, the better the location, and the better the foot/traffic count, the higher the lease.
In approx. 99% of cases with commercial real estate leasing, the small business owner doesn't have enough money to buy the real estate... thus leasing allows the small buisness owner to obtain a million dollar (in many cases multi-million) location for a fraction of the price.