Here is what happened after i spoke to everyone here :  It took me 4 yrs but last year finally i closed on my primary residence here in AZ..

Acquire the land through a seller-financed deal for the deed to the land and use it for collateral to cover the 20% down payment needed for the construction loan. 

However, the other friend (who is a loan broker) said it's better to do a note, so that I can refinance as a rate change in 2 months.

You might have several different loan options available to you depending on your needs (acquisition + rehab).

I would also carry the loan and establishing a penalty for early payoff (how much penalty?) 

I don't want to waive my right to use the final draw as leverage to ensure things are 100% complete.

Purchase price: $50,000 Cash invested: $16,000 Sale price: $127,000 Purchased with a 75% loan for cash flow.

I know they can be financed just like a stick built construction loan, however, my credit union is not doing construction loans right now and does not have a time frame for when they will (SECU).I want to use the land as down payment if possible and finance the modular and the site prep for it.Looking at getting a new modular duplex or a SFH. 

if so, you would need a bridge loan.

My question is, when buying a home, do most here use big banks for loans?