Gary,
One thing to consider, if I were your landlord I would be overjoyed to see you install a nice lift in my building, knowing that when it comes time for you to leave you're going to look at the cost to restore the building to unmolested state (to my satisfaction, not yours) compared to the price you can get for a now more used lift. You'll likely find that you cannot afford to move it, so you leave it behind and he now has a lift for nothing. Just saying, making improvements to another guys property doesn't generally pay back very well.