I have heard of leasing domains, but have never tried it. Google "leasing domains" and you should find a couple different companies that offer this service.
why risk u need to change nameservers only no need to transfer risk if the guy uses your domain for bad purposes like spam , racism
if you have domain which u are not using for develop then i can use your domain thats it you just change the nameservers to my hosting nameservers and i will host and earn by adsense or any other programs.
Well, mostly for the person owning the domain I think, for reasons as chandan123 suggests. But it can be just as bad if someone rents a domain from the owner, renter would also be treading on some thin waters now too aren't they? Owner can just switch names after collecting payment, or at any time they like. Still curious who's done this.
people who have large domain profile can do that also domains of generic terms will be used because domainer wont sell those names to another domainer they wait for the right price if they have stong keyword