You'll never get a "leachie" experience in ownership without buying a leachie.. except perhaps from rhacodactylus chahoua which seem to behave (and visually resemble somewhat) a whole lot like leachies but just a bit smaller.

If all you're looking for is a big gecko though, the other species already suggested are good things to look at.

I believe that Tokays are the most underrated gecko in herpetoculture.