Boaz,
yes, you can get it financed after you finish the build and have an Airworthiness Certificate, even if you paid cash in full. Its called a "cash back" loan, and I was able to get one for my plane.
Terms were around 4.25% and 20 years, with around 20% or more downpayment. I suppose it varies based on credit score, application, etc.
If you want more info you can contact me.

Rick