It is very realistic. I just closed on one yesterday. However, If you can’t produce a proof of funds letter or a Letter from a Private Lender (hard money lender) that says they will loan you the money, then you might just have to make offers on properties where they do not ask for these items. Yes, there are sellers (usually institutional lenders) who don’t require these items yet. I will say it is getting fewer and fewer here.
If you are dealing with a seller who is not a bank or HUD, you more often then not can submit offers without Proof of Funds. However if you do not have the cash, I do not sugget that you make cash offers.