I agree with Anna. If you don't ask....the answer is always No. It may be that they never have thought about selling it to YOU that way. Also, it may all depend on the landlord/seller's motivation. He/she may just want to sell it outright to get the money freed up, but they may not be in a hurry to get the cash out and may consider selling using owner financing.
When you talk to them (if you choose to) try to find out what THEIR motivation is and what THEY need. Then you can have a better idea of what their "hot bottom" is. This would allow you to formulate an offer that would be a win~win for both you and them.
If you do arrange some type of owner financing situation, PLEASE make sure to use Professionals who are familiar with the process (ie...Agent, Title Company, Real Estate Attorney) so that everything is written down, understandable, and transparent. If all items are agreed to upfront, it makes for a MUCH easier closing and fewer issues down the road.