I am in the middle of a land loan (for 10 acres) right now.. I have a banker that has been really good to work with. Let me know if you want his name.
That said - every bank/broker I spoke with said that land loans are the ones they have the most trouble with. For lots over 20 acres its going to be darn near impossible to find a lender in CO that will let you borrow without 60% (yes 60%) down (I have a whole long list of brokers/banks/credit unions that I tried). I know of a person outside of CO that will do it for 20% down but he is a little bit flakey. Most all of them are doing 3/1 or 5/1 on lots. Most everyone said to just do a 3/1 construction loan and then refi it under any equity you have in your existing home (if any). Its easier for them to write a construction loan than a lot loan. A couple of the banks I talked to said they were getting out of the land loans all toghether and are either selling off the notes or strongly enouraging their existing borrowers to sell. On more than one occasion I had the broker at a bank/CU offer to send me a list of lots they had and wanted to get rid of.
One thing that I found odd was even on lots where you have no intention to build several of the lenders still want soil and percolation tests done.