Buying land on lease

We are looking at buying a block of land to build on for eventual resale. This was subdivided off from the side of the guys block and is entered from up his driveway, then you turn left for his block, right for ours. They said the cheapest way for them to do it was to make a 99 year lease. If we got them to sign saying they will sign a title, is it possible to change this to a titled block
this is a really interesting topic. to create a title via lease do you still need to conform to all other requirements for creating a title? or can i just 'lease' off the back yard and there you go???