The options for this depend totally on location. Obviously some locations where developed lots exist are closer to being built out than others. What you may also need to consider is that there are restrictions against allowing mobile or manufactured housing on many developed lots, therefore many open lots will not accommodate your interests.
The other issue may be actual financing the balance of the purchase price. From what you are saying here it sounds like you will need financing for land. Improved or unimproved land financing is usually more difficult for a Buyer to obtain. Credit union and smaller banks tend to be more receptive with these things.
It is something that can be done, just need to know what your budget is and where you are willing to look.