it's really a nightmare to find the lender for land financing. Probably try this way. This company builds and sells the modular homes on their own lands and on yours. As i remember they finance the purchase of house+land combo. If you are interested, that's the website:
If there's land for sale without these permits in place, then the land is significantly worth less than if they had the proper permits.
You can call the town where you're looking - Bluepoint I think is either Town of Islip or Brookhaven. You can ask to speak with the building dept and tell them the dimensions of the lot, and they'll be able to tell you how large of a home you can build on that lot without a variance.
Buying land and building a mod home on Long Island isn't very common, because they're are so many local builders in this area and there's still tons of new construction all over the island - are you only looking in Blue Point?
When buying land, unless the owner is willing to hold the mortgage, you will have to pay cash for the land and then take out a building loan to build your home. However, before purchasing any land, you need to check the zoning and get the proper building permits in place. Your best bet is to hire an expeditor who is familiar with your particular town's zoning requirements to be able to get the permits approved. If I can assist you in this endeavor, please contact me.
Century 21 Princeton Properties