I think that leasing is a good option if the person who owns the name is willing to do that. The one caveat is that I'd want to do it as a lease-to-own deal. That would allow me to pay for the name over time, and own it after the final payment. I'd also want to be able to walk away from that name at any time by stopping my lease payments. That would all be spelled out in the contract.
As far as negotiation process, I usually send an email. Sometimes it is answered. Usually it is not. When it isn't, I then send a US letter to the registered domain owner. In my experience, that is rarely answered either. In my emails/letters I ask if they are willing to sell their domain, and then after contact we'll communicate either by email or phone to work out the terms from there. No magic formula, just standard negotiation where I want to pay a small amount, they want to charge an arm-and-leg and we find someway to meet in the middle. Maybe.
BTW, it's probably a good idea to have at least 5 to 10 different names you are considering. Unless you have beaucoup bucks or the domain owner is actively trying to sell the domain, it can be difficult to get a name.